WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Comprehensive WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment can help students make connections between concepts.

Concerns About Our Environment Class 10 WBBSE Notes

Environment : It is defined as the sum total of physical and biological factors that directly influence the survival, growth, development and reproduction of organisms.

Environmental chemistry: The branch of chemistry which deals with the study of various chemical phenomena occuring in the environment is called, environmental chemistry.

Environmental components of earth : Earth’s environment is composed of the following components :
1. Atmosphere 2. Hydrosphere 3. Lithosphere 4. Biosphere Among these the first three components are abiotic while the fourth one is biotic.

1. Atmosphere: This comprises a blanket of gaseous layer that extends to a height of about 1600 km above the surface of earth.
The atmosphere has been divided into four distinct zones. These are :

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere.

Different regions of atmosphere
WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 1

2. Hydrosphere: It includes all sources of water such as seas, oceans, lakes, rivers, fountains, polar regions, glaciers, ground water etc.

3. Lithosphere: It comparises of the solid crust of the earth, made up of rocks forming the outermineral cover. It includes soil, minerals, organic matters etc. and extends up to a depth of about 30 km from the earth’s surface.

4. Blosphere 3 It is that portion of the earth where living organisms exist and interact with one another and also with the non-living components.
Biosphere consists of all the three regions, e.g. soil, water, air etc. where living beings exist.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Temperature distribution with height above earth’s surfaces :

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 2

Ozone layer: In the lower region of the stratosphere (the region at the hieght of 15 km to 35 km from the ground) there exists a layer of ozone gas. This layer is called ozone layer or ozonosphere. Almost 90 % of total ozone gas exists in this layer.

Formation of ozone layer : O2(Oxygen molecule) present in the stratosphere absorbs UV (ultra violet) (λ = 255 nm ) radiation coming from the sum and decomposes to form oxygen atom (O). This atomic oxygen combines with oxygen molecule to form ozone molecule.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 3

Formation of O2 from O3 ; Ozone molecules also absorbs UV-radiation and gets converted into oxygen molecule (O2)

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 4

Fixation of quantity of ozone in the stratosphere: In the ozone layer of the stratosphere, these two opposite process (i.e. formation of ozone molecule and the decomposition of ozone molecule) occur in a cyclic order and finally attains a state of equilibrium. Because of the existense of such an equilibrium state, quantify of ozone in the stratosphere remains fixed.

Role of ozone layer in the environment : Ozone layer absorbs most of the harmful UV-radiation emitted by the sun because this ray is utlised in the production and decomposition of ozone.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Harmful effect of UV-radiation:

  1. ultraviolet radiation causes cancer in human skin.
  2. damages the cornea of the eyes and develops premature cataract.
  3. In addition, immunity against diseases and fertility in living beings decreases.

Ozone hole (Depletion of Ozone layer); The phenomenon of thinning of the Ozone layer of the stratosphere is known as depletion of ozone layer or ozone hole.
In 1982, the British scientist Jo Foreman first observed ozone hole.

Causes of depletion of ozone layer or formation of ozone hole:; Due to the influx of several foreign substances into the atmosphere, the rate of decomposition of ozone has far exceeded than that of its formation. This has resulted in the thinning of ozone layer in the stratosphere almost everywhere.

The factors which accelerate the ozone depletion are as follows :

Some chemical substances belonging to the class of chlorofluorocarbons (Freons or CFC ) are mainly responsible for the formation of ozone hole.

Name Formula Trade Name
Trichloro fluoro methane CFCl3 Freon-1
Dichloro difluoro methane CF2Cl2 Freon-12
Dichloro fluoro methane CHCl2F Freon-22
Dichloro trifluoro ethane CHCl2-CF3 Freon-113
Dichloro fluoro ethane CH3-CCl2F Freon-1146

Use of the above mentioned chemicals :

  • refrigerants
  • propellants in aerosols
  • foaming agent in plastic production
  • as solvents for various purposes.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

A cyclic process continues, which eventually causes depletion of ozone layer.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 5

It has been experimentally found that a single Cl atom is capable of decomposing millions of O3 molecules.

Halocarbons : It has been found experimentally that halons i.e. halocarbons which are generally used as fire extinguishers and as pesticides e.g. Halon-1301 i.e. bromo trifluoro methane (CF3 Br), Halon-1211 i.e. bromochloro difluoro methane (CF2BrCl). Halons are stable in the troposphere. But in the stratosphere, they absorb UV-radiation and decompose to produce active bromine atoms ( Bi). Thus produced active Br atoms convert ozone molecule of ozone layer to oxygen molecule and free radical bromine monoxide ( BrO ). They produced bromine monoxide (BrO) reacts with more ozone to give more oxygen and active Br atoms. In this way, the entire process proceeds continuously in a cyclic manner which lead to decay of the ozone layer.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 6

Oxides of Nitrogen (NO, NO2) : The gaseous oxide of nitrogen is produced due to human activity or naturally in the troposphere. Major portion of this gas is produced in the exhaust gases of supersonic planes flying in the stratosphere and thus the gas is added directly into the stratosphere.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Here NO (Nitric oxide) gas comes in contact with the ozone and reacts to form NO2and O2. The NO thus reacts with Oxygen atoms and formed NO2due to the decomposition of ozone molecules by the UV-rays. Nitrogen dioxide (NO2) reacts with Oxygen atoms to produce back Nitric Oxide (NO) gas. This explains why the ozone molecules undergo continuous decomposition although the quantity of Nitric oxide (NO) is not diminised.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment 7

Green house: Green house is a large chamber made of glass on the soil. When the plants of tropical countries are taken to cold countries, they cannot adapt themselves to the climatic conditions of the cold countries.

Green house gases: These are some gases which are present in earth’s atmosphere e.g. carbon dioxide (CO2), methane (CH_4), water vapour (H2O), chlorofluoro Carbon (CFC), ozone (O3), nitrous oxide (N2O).

The green house gases form a layer surrounding the earth’s surface which act like that of the glass walls and roof of the green house and keep the atmosphere of earth’s surface warmer. These gases are known as green house gases.

Green house effect: The natural process by which a layer of green house gases present in the atomsphere surrounding the earth’s surface, instead of allowing the infrared radiation reflected by earth’s surface to pass out into the outer space, partly absorbs the radiated heat and reflects back the rest to the earth’s surface and thus keeps the surface of the earth and the adjacent atmosphere warm, which is suitable for the existence of the living beings, is known as green house effect.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Global warming : It has been observed that in the last few centuries the average temperature of the earth is gradually increasing. For example, during the period from 1800-1900 AD, the average increase of the earth’s temperature was found to be 0.4° C and during the period 1900-2000 AD this increase in temperature is 1° C. So it cannot be denied that the natural environment is gradually becoming warmer.

The phenomenon of gradual increase of temper all over the world is called global warming.

Causes for the increasing concentration of green house gases in the atmosphere :

  1. Huge amount of coal is burnt daily in the thermal power stations for the generation of electricity.
  2. Excessive use of nitrogenous fertilizers in agriculture is the cause of increasing amount of nitrous oxide and oxides of nitrogen in the atmosphere.
  3. Combustion of huge amount of petrol and diesel in the automobiles and forest fires are the causes for the increase of carbon dioxide in the atmosphere.
  4. Extensive use of coal, wood, LPG etc., as fuels for the cooking purpose and to meet the other needs of the growing population. In consequence of which high amount of carbon dioxide gas is being added to the atmosphere.
  5. Due to the increase of paddy field, marshy lands, waste organic matters, the amount of methane gas in the atmosphere is going on increasing.

Some preventive meacures to reduce emiseion of green hotuse gases;

  1. In order to decrease the amount of carbon dioxide in the atmosphere the use of fossil fuels e.g. wood, coal, petrol, diesel, kerosene, L.P.G. etc., should be reduced as far as possible.
  2. Afforestation must be encouraged so that more carbon dioxide are absorbed by plants.
  3. Use of chlorofluoro carbon (CFC) must be stopped totally.
  4. Deforestation must be totally stopped legally.
  5. Instead of using coal, electric energy can be produced by using solar energy, tidal energy, wind energy. Electricity may be produced by using nuclear energy and hydroelectricity.

The calorific value of a fuel : It is the quantity of heat produced by its combustion at constant pressure under hormal’ (standard) conditions (i.e. to 0°C and under a pressure of 76 cm Hg pressure).

Higher calorific values for some common fuels: Coke, oil, wood, hydrogen etc.

Necessity of conservation of fossile fuels :

Advantages of Fossils fuels

Easily available : Since these fossil fuels have been of such a great source of energy, more and more extractions are going on every day.

Produce large amount of Energy : Fossil fuels are easily combustible.

High Caloricfic value : All energy produced has some calorific value. The more the value, the more effective it is.

Stability : The fossil fuels are composed of the molecules of carbon and hydrogen. This makes them very stable.

Transportation : This industries need regular supply of fossil fuel like oil, gas and coal. The biggest advantage of using fossil fuels is that they can be easily stored and transported from one place to another.

Abundantly available : Though every effort is made to make the usage of alternative fuels popular, still fossil fuels are most common ones in use. This is because, these are very easily available.

Low cost : Fossil fuels are available all over the world and the methods to extract energy from them are also not that expensive.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Easy set up : Since they are widely available, the construction of fossil fuel power plant can take any where in the world as long as they get large quantities of fossil fuels to feed them.

Sources of energy :

Solar energy: Solar power harvests the energy of the sun through using collector panels to create conditions that can be turned into a kind of power. Large solar panel fields are often used in desert to gather enough power to charge small substations, and many homes use solar systems to provide for hot water, cooling and supplement their electricity.

Wind energy: Wind power is becoming more and more common. The new innovations that are allowing wind forms to appear are making them a more comman sight. By using large turbines to take available wind as the power to turn, the turbine can then turn a generator to produce electricity.

Geothermal Energy: It is the energy that is produced from beneath the earth. It is clean sustainable and environment friendly. High temperature are produced continuously inside the earth’s crust by the slow delay of radioactive particles. Hot rocks present below the earth heats up the water that produces steam. The steam is then captured that helps to move turbines. The rotating turbines then power the generators.

The biggest disavantage with geothermal energy is that it can only be produced at selected sites throughout the world. The largest group of geothermal power plants in the world is located at the Geysers, a geothermal field in california, united states.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Hydroyen Energy : Hydrogen is available with water (H2O) and is most common element available on earth. Water contains two-thirds of hydrogen and can be found in combination with other elements. Once it is separated, it can be used as a fuel for generating electricity.

Hydrogen is a tremendous source of energy and can be used as a source of fuel of power ships, vehicles, homes, industries and rockets. It is completely renewable, can be produced on demand and does not leave any toxic emissions in the atmosphere.

Tidal Energy : Tital energy uses rise and fall of tides to convert kinetic energy of incoming and outgoing tides into electric energy. The generation of energy through tidal power is mostly prevalent in coastal areas. Huge investment and limited availability of sites are few of the draw-backs of tidal energy. When there is increased height of water levels in the ocean, tides are produced which rush back and forth in the ocean. Tidal energy is one of the renewable source of energy and produce large energy even when the tides are at low speed.

Wave Energy : Wave energy is produced from the waves that are produced in the oceans. Wave energy is renewable, environment-friendly and causes no harm to atmosphere. It can be hardnessed along coastal regions of many countries and can help a country to reduce its dependance on foreign countries for fuel. Producing wave energy can damage marine ecosystem and can also be a source of disturbance to private and commercial vessels. It is highly dependent on wavelength and can also be source of visual and noise pollution.

Hydroelectric Energy: Many people are not aware about that most of the cities and towns in the world rely on hydropower. Every time you see a major dam, it is providing hydropower to an electrical station somewhere. The power of water is used to turn generatots to produce the electricity that is then used. The problems faced with hydropower right now have to do with against of the dams.

Biomass Energy: It is produced from organic material and is commonly used throughout the world chlorophyll present in plants captures the Sun’s energy by converting carbon dioxide from the air and water from the ground into carbohydrates through the process of photosynthesis. When the plants are burned, the water and carbon dioxide is again released back into the atmosphere. Biomass generally include crops, plants, trees, yard clippings, wood chips and animal wastes. Biomass energy is used for heating and cooking in homes and a fuel in industrial production. This type of energy produces large amount of CO2into the atmosphere.

WBBSE Class 10 Physical Science Notes Chapter 1 Concerns About Our Environment

Nuclear Power: While nuclear power remains a great subject of debate as to how safe it is to use and whether or not it is really energy efficient when you take into account the waste it produces – the fact is it remains one of the major renewable source of energy available to the world. The energy is created through specific nuclear reaction, which is then collected and used to power generators. While almost every country has nuclear generators, there are moratorium on their use or construction as scientists try to resolve safely and disposal issues for waste.

Fossil Fuels (Coal, Oil and Natural Gas): When most people talk about the different sources of energy they list natural gas, coal and oil as the options – these are all considered to be just one source of energy from fossil fuels.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions can serve as a valuable review tool before exams.

Electricity and Chemical Reactions Bonding Class 10 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1.
The electrolyte is
(A) Glycerine
(B) Sugar
(C) Sodium chloride
(D) Glucose
Answer:
(C) Sodium chioride

Question 2.
The vessel in which electrolysis takes place is called :
(A) Voltameter
(B) Voltmeter
(C) Calorimeter
(D) Ammeter
Answer:
(A) Voitameter

Question 3.
Which of the following substances is non-metal but conductor :
(A) Nickel
(B) Iron
(C) Silver
(D) Gas carbon
Answer:
(D) Gas carbon

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 4.
A silver substance is to be gold plated which is to be used as anode:
(A) Pt
(B) Au
(C) Cu
D) Fe
Answer:
(B) Au

Question 5.
What is the volume ratio of produced hydrogen and oxygen from electrolysis of water ?
(A) 1 : 2
(B) 2 : 1
(C) 2 : 3
(D) 1 : 1
Answer:
(B) 2 : 1

Question 6.
Which agent conducts electricity during electrolysis ?
(A) water
(B) ion
(C) atom
(D) molecule.
Answer:
(B) ion

Question 7.
Molter sodium chloride conducts electricity due to the presence of:
(A) free electrons
(B) free ions
(C) free molecules
(D) atoms of sodium and chlorine
Answer:
(B) free ions

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 8.
An electrolyte :
(A) gives ions only when dissolved in water
(B) gives ions only when electric current is passed
C) has ions even in the solid state
(D) does not give complex ions in solution
Answer:
(C) has ions even in the solid state

Question 9.
The amount of an ion discharged during electrolysis is not directly proportional to:
(A) resistance
(B) time
(C) current
(D) chemical equivalent
Answer:
(A) resistance

Question 10.
Which one of the following solutions will conduct electricity ?
(A) Magnesium chloride in water
(B) Sugar in water
(C) Sugar in ethyl alcohol
(D) lodine in ethyl alcohol
Answer:
(A) Magnesium chloride in water

Question 11.
In the electrolysis of NaCl :
(A) Cl ion is oxidised at anode
(B) Cl ion is reduced at anode
(C) Cl ion is oxidised at cathode
(D) Cl ion is neither reduced or oxidised
Answer:
(A) Cl ion is oxidised at anode

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 12.
On the electrolysis of aQuestion solution of sodium sulphate, on cathode, we get :
(A) Na
(B) H2
(C) SO2
(D) SO3
Answer:
(A) Na

Question 13.
On electrolysis a solution of dilute H2 SO4 using platinum electrodes, the gas evolved at the anode is :
(A) SO2
(B) SO3
(C) O2
(D) H2
Answer:
(C) O2

Question 14.
When a copper wire is placed in solution of AgNO3, the solution acquires blue colour. This is due to the formation of:
(A) Cu+2 ions
(B) Cu+ ions
(C) soluble complex of copper with AgNO3
(D) none of these
Answer:
(A) Cu+2 ions

Question 15.
Flow of current in an electrolyte is due to :
(A) atoms
(B) electrons
(C) ions
(D) none of these
Answer:
(C) ions

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 16.
Use of electrolysis is :
(A) Electroplating
(B) Electrorefining
(C) Both A And B
(D) none of these
Answer:
(C) Both A And B

Question 17.
Electroplating was discovered by :
(A) Faraday
(B) Arrhenius
(C) Newton
(D) Dalton
Answer:
(A) Faraday

Question 18.
Which of the following is a strong electrolyte :
(A) Ca(NO3)2
(B) HCN
(C) H2 SO3
(D) NH4 OH
Answer:
(A) Ca(NO3)2

Question 19.
The electroplating with chromium is under taken because :
(A) electrolysis of chromium is easier
(B) chromium can form alloys with other metals
C) chromium gives a protective and decorative coating to the base metal
(D) of high reactivity of chromium metal
Answer:
(C) Chromium gives a protective and decorative conting to the base metal.

Question 20.
Pure water does not conduct electricity because it:
(A) has low boiling point
(B) is neutral
(C) is almost unionised
(D) is readily decomposed
Answer:
(C) is almost unionised

Question 21.
During electrolysis of CuSO4, the product collected at the anode is:
(A) Oxygen
(B) Hydrogen
(C) Copper
(D) Sulphate
Answer:
(A) Oxygen

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 22.
During the electrolysis of fused sodium chloride, the anodic reaction is :
(A) reduction of sodium ions
(B) oxidation of sodium ions
(C) reduction of chloride ions
(D) oxidation of chloride ions
Answer:
(D) oxidation of chloride ions

Question 23.
The unit of quantity of electricity is :
(A) volt
(B) coulomb
(C) ampere
(D) ohm
Answer:
(B) coulomb

Question 24.
In electroplating copper with silver, the both solution used is of K[Ag(CN)2] instead of AgNO3 because on account of complex formation :
(A) a thin coating of silver is obtained
(B) Ag+ ions are completely removed from the solution
C) expenses on electricity are reduced
(D) availability of Ag+ ions in solution is so reduced that they are not replaced by copper ions.
Answer:
(D) availability of Ag+ ions in solution is so reduced that they are not replaced by copper ions.

Question 25.
For the electroplating of nickel, nickel sulphate is mixed with :
(A) water
(B) nitric acid
(C) boric acid
(D) H2 SO4 as electrolyte
Answer:
(C) boric acid

Question 26.
During electrolysis of copper using copper electrodes of copper in solution is :
(A) increased
(B) decreased
(C) unaltered
(D) None of these
Answer:
(C) unaltered

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 27.
Which one of the following is a non-electrolyte ?
(A) NaCl
(B) HCl
(C) urea
(D) H2 SO4
Answer:
(C) urea

Question 28.
Which one is a strong electrolyte ?
(A) NaOH
(B) NH4 OH
(C) CH3 COOH
(D) glucose
Answer:
(A) NaOH

Question 29.
In electrolytic solution electricity is conducted by :
(A) electrons
(B) atoms
(C) ions
(D) molecules
Answer:
(C) ions

Question 30.
Electrolysis of CuSO4 solution using Cu-electrodes, the products at electrodes are :
(A) Cu-at anode
(B) Cu+2 at anode
(C) H2 at cathode
(D) O2 at anode
Answer:
(B) Cu+2 at anode

Question 31.
Reaction takes place during electrolysis at electrodes are :
(A) oxidation at cathode
(B) reduction at anode
(C) reduction at cathode
(D) no chemical reaction
Answer:
(C) reduction at cathode

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 32.
Which one is an inert electrode?
(A) copper
(B) iron
(C) platinum
(D) graphite
Answer:
(D) graphite

Question 33.
During the electroplating of a spoon with silver, the reaction taking plac at anode is.
(A) Ag+2+2e → Ag
(B) Ag-2 e → Ag+2
(C) Ag-e → Ag+
(D) Ag++ e → Ag
Answer:
(C) Ag-e → Ag+

Question 34.
The reaction that takes place at anode is :
(A) oxidation
(B) reduction
(C) substitution
(D) acid-base
Answer:
(A) oxidation

Question 35.
Which of the following is a weak electrolyte?
(A) CuSO4
(B) KOH
(C) H2 SO4
(D) CH3 COOH
Answer:
(D) CH3 COOH

Question 36.
Identify the strong electrolyte
(A) ammonium hydroxide
(B) acetic acid
(C) nitric acid
(D) carbonic acid
Answer:
(C) nitric acid

Question 37.
Choose the wrong statement :
(A) Pure water is a poor conductor of electricity
(B) Cations carry positive charges
(C) Anions move towards anode during electrolysis
(D) Oxidation takes place at the cathode
Answer:
(D) Oxidation takes place at the cathode

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

Question 38.
11.2 L of a gas is evolved at cathode during electrolysis of water. Amount of gas evolved at anode at the same temperature and pressure is :
(A) 5.6 L
(B) 11.2 L
(C) 22.4 L
(D) 44.8 L
Answer:
(A) 5.6 L

Question 39.
During copper refining which is used as anode?
(A) platinum
(B) pue copper
(C) graphite
(D) impure copper
Answer:
(D) impure copper

Question 40.
Energy conversion during electrolysis is :
(A) chemical to electrical
(B) electrical to chemical
(C) electrical to mechanical
(D) mechanical to electrical
Answer:
(B) electrical to chemical

Fill in the blanks :

1. _______ is a vessel in which electrolysis is carried out.
Answer:
Voltameter.

2. In electrolysis of water, hydrogen accumulates at the cathode and _______ at the anode.
Answer:
oxygen.

3. The decomposition process of electrolytes into ions is known as _______ dissociation.
Answer:
ionic.

4. In electrolyte electrical conduction occurs by migration of _______.
Answer:
ions.

5. An electrolyte is a compound that conducts electricity in fused or solution state and at the same time _______ chemically.
Answer:
decomposes.

6. In the electrolysis, electric current enters the electrolyte solution through the anode and leaves through the _______.
Answer:
cathode.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

7. Aluminium is extracted by the electrolysis of a molten mixture of bauxite and _______.
Answer:
cryolyte.

8. In the electrolysis of water, it is found that at the same temperature and pressure _______ olume of oxygen and two volumes of hydrogen are evolved.
Answer:
one.

9. Compounds which in the _______ state or in aqueous solution can conduct electricity and are decomposed chemically yielding new substances are called electrolytes.
Answer:
fused.

10. Mercury is a good conductor of electricity but is not an _______.
Answer:
electrolyte.

11. Rubber is _______ of electricity.
Answer:
non-conductor.

12. In electro-plating, the plating metal is used as _______.
Answer:
cathode.

13. The process of depositing a thin layer of one metal over another metal with the help of an electric current is called _______.
Answer:
electroplating.

14. _______ is a semi-conductor.
Answer:
Silicon.

15. 2 H + 2 e →
Answer:
2 H.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

16. The aqueous solution of sugar is _______.
Answer:
non-electrolyte.

17. _______ is used as an electrolyte for the electroplating of Nickel.
Answer:
Nickel sulphate (NiSO4) with boric acid (H3 BO3)

18. The aqueous solution of sodium hydroxide is _______.
Answer:
electrolyte.

19. In electrolysis _______ conduct electricity.
Answer:
ions.

20. Between H and Al3+ _______ ion is discharged first at cathode.
Answer:
H.

21. Between Br and OH _______ ion is discharged first at anode.
Answer:
OH

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

22. Compounds which do not conduct an electric current is aqueous solution or in the molten state are termed as_______.
Answer:
non-electrolytes.

23. The _______ of the total number of molecules of an electrolyte dissociating into free ions is known as the degree of dissociation.
Answer:
fraction.

24. The products formed during electrolysis are deposited or liberated only at the _______.
Answer:
electrodes.

25. _______ changes that occur during electrolysis at the electrodes start as soon as the current is switched on and cease as soon as it is switched off.
Answer:
Chemical.

26. Electrolysis of molten NaCl produces and at cathode _______ and _______ anode respectively.
Answer:
Na, Cl2

27. With increase of temperature of the electrolytic solution its conductivity will _______.
Answer:
increase

28. Example of strong electrolyte is _______.
Answer:
H2 SO4

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

29. It is the _______ which are responsible for conduction of electricity in electrolytic solution.
Answer:
ions

30. In electroplating with gold the anode used is _______.
Answer:
pure gold plate.

31. During gold plating, the objects to be coated with gold are used as _______.
Answer:
cathode

32. During silver plating the electrolyte used is _______.
Answer:
potassium argentocyanide

33. In case of metals, current is carried by _______.
Answer:
electrons

34. In case of aqueous solution of an electrolyte, current is carried by _______.
Answer:
ions

35. In case of _______ electrolyte, it dissociates completely when dissolved in water.
Answer:
strong

36. In case of _______ electrolyte, it dissociates partially when dissolved in water.
Answer:
weak

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

37. _______ is connected to the positive terminal of the battery.
Answer:
Anode

38. _______ is connected to the negative terminal of the battery.
Answer:
cathode

39. During electrolysis of a mixture of alumina and cryolite _______ is used to lower the melting point of pure alumina.
Answer:
fluorspar

40. During electrolysis of copper sulphate using copper electrodes, the weight of anode _______.
Answer:
decreases

State whether the following statement is True or False : VSA

1. Little amount of acid is added to water during electrolysis of water.
Answer:
True

2. Through electroplating, a layer of high reactive metal is applied over a low reactive metal is applied over a low reactive metal.
Answer:
False

3. During electrolysis electrolytes conduct electricity through electrons.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

4. Method of electrolysis is utilized during extraction of metals such as aluminium, sodium etc.
Answer:
True

5. During electrolysis of water, hydrogen and Oxygen gas are produced at a volume ratio of 1: 2
Answer:
False

6. Pure water is a good conductor of electricity.
Answer:
False

7. Sodium chloride can conduct electricity in molten state.
Answer:
True

8. During electrolysis, Oxidation takes place at cathode and reduction takes place at anode.
Answer:
False

9. When an electrolyte is dissolved in water, ions ae formed.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.3 Electricity and Chemical Reactions

10. When an electrolyte is dissolved in water, ions are formed, hence the solution becomes charged.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding can serve as a valuable review tool before exams.

Ionic and Covalent Bonding Class 10 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1.
Which class of substance is a common component of all electrovalent compounds ?
(A) Metal
(B) Non-Metal
(C) Metalic oxide
Answer:
(A) Metal

Question 2.
In electrovalency which component element gains electron?
(A) The metallic component
(B) All the components
(C) The nonmetallic component
Answer:
(C) The nonmetallic component

Question 3.
Which of the following bonds will be non-polar ?
(A) N-H
(B) C}-H
(C) F-F
(D) O-H
Answer:
(C) F-F

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 4.
Sodium conducts electricity because :
(A) It is a soft alkali metal
(B) It has only one electron in-the outermost orbit
(C) It has mobile electrons
(D) It gives hydrogen gas with water.
Answer:
(C) It has mobile electrons

Question 5.
Which of the following is more covalent ?
(A) SnCl4
(B) SnBr4
(C) Snl4
Answer:
(C) SnI4

Question 6.
Which of the following is the strongest bond?
(A) F-F
(B) Br-F
(C) Cl-F
(D) 1 – F
Answer:
(A) F-F

Question 7.
The high reactivity of fluoring is due to :
(A) Lower energy of F-F bond
(B) High energy of F-F bond
(C) Fluorine is gas at room temperature.
Answer:
(A) Lower energy of F-F bond

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 8.
The element with the atomic number 9 can exhibit an oxidation state of
(A) +1
(B) -1
(C) +3
(D) -3
Answer:
(B) -1

Question 9.
Which of the following statements does not fully describe oxygen ?
(A) It is diatomic melecule
(B) It is covalently bonded
(C) It has a single bond
(D) It is low boiling liquid
Answer:
(A) It has a single bond.

Question 10.
Polar bond is formed between two atoms which have :
(A) low ionisation energies
(B) similar electronegativity values
(C) high electron affinities
(D) different electronegativity values
Answer:
(D) different electronegativity values

Question 11.
Which among the following bonds shows the maximum bond strength?
(A) Sigma bond
(B) π-bond
(C) Co-ordinate bond
(D) Hydrogen bond
Answer:
(A) Sigma bond

Question 12.
C-C bond length In saturated compound is :
(A) 1.47 A°
(B) 1.38 A°
(C) 1.54 A°
(D) 1.51 A°
Answer:
(C) 1.54 A

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 13.
The types of bonds present in CuSO4, 5 H2O are only :
(A) Electrovalent and covalent
(B) electrovalent and co-ordinate covalent
(C) electrovalent, covalent and co-ordianate covalent
(D) covalent and co-ordinate covalent
Answer:
(C) electrovalent covalent and co-ordianate covalent

Question 14.
Which of the following has an electrovalent linkage ?
(A) MgCl2
(B) CH4
(C) SiCl4
(D) BF3
Answer:
(A) MgCl2

Question 15.
Which of the following exists as monoatomlc ?
(A) Sulphur
(B) Helium
(C) Fluorine
(D) Phosphorus
Answer:
(B) Helium

Question 16.
Which of the following compounds is ionic or electrovalent ?
(A) CCl4
(B) CaCl2
(C) SnCl4
(D) PCl5
Answer:
(B) CaCl

Question 17.
Which of the following is the most polar ?
(A) CCl4
(B) CHCl2
(C) CH3 OH
(D) CH3 Cl
Answer:
(B) CH Cl

Question 29.
Percentage of noble gas present in air is :
(A) 5 %
(B) 0.01%
(C.) 1 %
(D) 21 %
Answer:
(C) 1 %

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 30.
In electrovalent bond there is electron :
(A) between two atoms
(B) between two atoms of molecules
(C) between two molecules
(D) none of these
Answer:
(D) None of these

Question 31.
The shape of NaCl crystal is :
(A) tetrahedral
(B) octahedral
(C) hexagonal
(D) icosohedral
Answer:
(B) Octahedral

Question 32.
How many bonding electrons are there is CO2 ?
(A) 1
(B) 2
(C) 4
(D) 8
Answer:
(D) 8

Question 33.
The number of covalent bonds in C2H4 is:
(A) 4
(B) 5
(C) 6
(D) 7
Answer:
(C) 6

Question 34.
Which compound contains both electrovalency and covalency?
(A) NaCl
(B) HCl
(C) CaCl2
(D) KCN
Answer:
(D) KCN

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 35.
Which of the following molecules is a heteronuclear covalent compound?
(A) H2
(B) Cl2
(C) NH3
(D) F2
Answer:
(C) NH3

Question 36.
Which one is a covalent compound?
(A) Sugar
(B) Common salt
(C) ethanol
(D) glucose
Answer:
(B) Common salt

Question 37.
Aqueous solution of which of the following will not conduct electricity?
(A) Sodium chloride
(B) Sugar
(C) Hydrochloric acid
(D) Magnesium chloride
Answer:
(B) Sugar

Question 38.
NaCl is an ionic compound. Which of the following statements is correct?
(A) NaCl is solid at room temperature
(B) NaCl is not soluble in water
(C) Aqueous solution of NaCl can conduct electricity
(D) NaCl has high melting point
Answer:
(B) NaCl is not soluble in water

Question 39.
How does calcium obey the octet rule when reacting to form compounds?
A it gains electrons
(B) it gives up electrons
C) it does not change the number of electrons
(D) Calcium does not obey the octet rule
Answer:
(B) it gives up electrons

Question 40.
What is the charge on the cation in the ionic compound sodium sulphide?
(A) 0
(B) +1
(C) +2
(D) +3
Answer:
(B) +1

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

Question 41.
An element M burns in oxygen to form an ionic compound MO. What shall be the formulla of its chloride?
(A) M2 Cl
(B) MCl
(C) MCl2
(D) MCl3
Answer:
(C) MCl2

Question 42.
Three elements P, Q and R have atomic number 10, 17, 20. Identify the wrong statement.
(A) P is an inert gas
(B) Q is a non-metal
(C) R is a metal
(D) P and R are both inert gas
Answer:
(D) P and R are both inert gas

Question 43.
The property which is characteristic of an lonic compound is that :
A it is a weak electrolyte
(B) It is usually volatile
C) it has high melting point
(D) it often exists as liquid
Answer:
(C) it has high melting point

Fill in the blanks :

1. Covalent compounds do not produce ______ states, so these are non-electrolytes.
Answer:
ions.

2. Almost all the participants in a covalent compound are _______.
Answer:
non-metals.

3. In ammonia molecule, each hydrogen atom is related with one pair of shared _____ so covalency of hydrogen is 1 .
Answer:
electrons.

4. Valency of an element in a covalent compound is measured by its relation to the number of shared ______.
Answer:
electron-pairs.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

5. Valency of an element in an electrovalent compound is the number of ______ an atom of it gains or loses in forming the compound.
Answer:
electrons.

6. Chemical bond is a strong force of attraction that holds together _______ in a molecule or crystal.
Answer:
atoms.

7. Electrovalency is the type of chemical bonding established by actual transference of one or more ________ electron (s).
Answer:
valence.

8. In covalency two or more atoms of the same or different non-metallic elements combine chemically by the process of _______ one or more pairs of valence electrons.
Answer:
sharing.

9. Electrovalent compounds are formed by strong attractive electrostatic ________ between ions of opposite charge.
Answer: forces.

10. In the formation of all electrovalent compounds a _______ is involved.
Answer:
metal.

11. Formation of NaCL involves _______ in energy.
Answer:
decrease.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

12. Ionic compounds have ________ melting and boiling points.
Answer:
high.

13. NH3 involves covalent bonding but NH4 ion involves _______.
Answer:
co-ordinate bonding.

14. The relative tendency of a bonded atom to attract electrons is expressed by the term _______.
Answer:
electronegativity.

15. Low ionisation energy and high electron affinity favour _______ bond formation.
Answer:
ionic.

16. Covalent compounds are generally soluble in _______ solvents.
Answer:
non-polar.

17. Solid NaCI is a _______ conductor of electricity.
Answer:
bad.

18. Among the compounds, NaCl, KCI, CsCI, the one with the greatest ionic character is _______.
Answer:
CsCI.

19. Helium atom contains _______ electron.
Answer:
two (2)

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

20. In atom number of protons is equal to number of _______.
Answer:
electrons.

21. Sodium atom contains _______ electron in its outermost shell.
Answer:
one (1).

22. _______ are formed by releasing electrons from atom.
Answer:
Positive ions.

23. An electrovalent compound being composed of ions is soluble in ionising solvents like _______.
Answer:
water.

24. Covalent compounds have _______ melting and boiling point.
Answer:
low.

25. Isomerism is found in _______ compounds.
Answer:
covalent.

25. Chemical reactions of covalent compounds are usually _______.
Answer:
slow.

26. Ionic compounds are soluble in _______ solvents.
Answer:
polar.

27. Theory of covalent bond formation was proposed by _______.
Answer:
Lewis

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

28. Theory of tonic bond formation was proposed by _______.
Answer:
Kossel

29. Number of bonds present in nitrogen molecules are _______.
Answer:
3

30. Krypton and Xenon were discovered by _______.
Answer:
Ramsay and Traves

31. The atomic number of an element is 17, It should gain _______ electron to attain the electronic configuration of its nearest inert gas.
Answer:
one

32. In forming nitrogen molecule _______ electrons are shared by each atom of nitrogen.
Answer:
3

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

33. The atomic number of an element is 11, It should lose _______ electron to attain the electronic configuration of its nearest inert gas.
Answer:
one

34. Two chlorine atoms comblne to form a molecule. The bond between them is known as _______ bond.
Answer:
covalent

35. Magnesium chloride is _______ compound.
Answer:
ionic

36. A covalent compound is usually soluble in solvents having _______ dielectric constant.
Answer:
low

37. The chemical bond formed by the sharing of electrons between two atoms is known as _______ bond.
Answer:
covalent

38. Melting point and boiling point of an tonic compound are generally _______.
Answer:
high

State whether the following statement is True or False : VSA

1. Between Na and Na+, Na+is more stable.
Answer:
True

2. Melting points and boiling points of ionic compounds are generally lower than those of covalent compounds.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

3. Ionic compounds consist of tons and not molecules.
Answer:
True

4. An ionic bond is formed between a metal and a non-metal.
Answer:
True

5. Covalent bond is formed when a non-metal combines with another non-metal.
Answer:
True

6. In forming oxygen molecule, 2 electrons are shared by each atom of oxygen.
Answer:
True

7. No bonds are 100 % ionic or 100 % covalent.
Answer:
True

8. Like ionic compounds, covalent compounds can also conduct electricity when in solution.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.2 Ionic and Covalent Bonding

9. Ethene (or ethylene) has one double bond and 4 single bonds.
Answer:
True

10. Covalent compounds are usually liquid or gaseous under ordinary temperature and pressure.
Answer:
True

11. Ionic bonds are non directional in nature.
Answer:
True

12. The solution of hydrogen chloride in benzene is not at all acidic.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements can serve as a valuable review tool before exams.

Periodic Table and Periodicity of the Properties of Elements Class 10 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1. The basis of modern periodtc table is :
(A) atomic volume
(B) atomic number
(C) atomic weights
(D) atomic size
Answer:
(A) atomic volume.

Question 2.
Which of the following has the maximum value of electron affinity?
(A) F
(B) Cl
(C) Br
(D) I
Answer:
(B) Cl

Question 3.
The elements of group IIA and IIA are known as :
(A) s-block elements
(B) p-block elements
(C) typical elements
(D) transition elements
Answer:
(A) s-block elements

Question 3.
Characteristic of transition elements is incomplete :
(A) d-orbitals
(B) f-orbitals
(C) p-orbitals
(D) s-orbitals
Answer:
(A) d-orbitals

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 4.
The electron affinity of inert gases is likely to be :
(A) high
(B) negative
(C) positive
(D) zero
Answer:
(D) zero

Question 5.
The element with the highest first ionization potential is :
(A) boron
(B) carbon
(C) nitrogen
(D) oxygen
Answer:
(C) nitrogen

Question 6.
In second period, if we move from Li to F, there is regular decrease in :
(A) atomic mass
(B) atomic radius
(C) electronegativity
(D) ionization potential
Answer:
(B) atomic radius

Question 7.
Compared to the first ionisation potential of an atom, the second is:
(A) the same
(B) greater
(C) smaller
(D) negligible
Answer:
(B) greater

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 8.
Which has the largest first ionization energy ?
(A) Li
(B) Na
(C) K
(D) Rb
Answer:
(A) Li

Question 9.
The outermost electronic configuration of the most electronegative element is :
(A) ns2 np3
(B) ns2 np4
(C) ns2 np5
(D) ns2 np6
Answer:
(C) ns2 np3

Question 10.
Which one of the following has the largest size ?
(A) Br
(B) I
(C) I
(D) \(I^{\oplus}\)
Answer:
(B) I

Question 11.
Which one of the following is the smallest in size ?
(A) N3-
(B) O2-
(C) F
(D) Na+
Answer:
(D) Na

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 12.
All the elements in a group in the periodic table have the same:
(A) atomic weight
(B) atomic number
(C) number of electrons available for bonding
(D) atomic mass
Answer:
(C) number of electrons available for bonding.

Question 13.
‘The law of triads’ is applicable to the following :
(A) Cl, Br, I
(B) H, O, N
(C) Na, Ne, Ca
(D) None of the above
Answer:
(A) Cl, Br, I

Question 14.
The element in the third group and third of periodic table is :
(A) B
(B) Na
(C) Al
(D) Mg
Answer:
(C) Al

Question 15.
The law of octaves applies to :
(A) B, C, N
(B) As, K, Ca
(C) Be, Mg, Ca
(D) None of the above
Answer:
(C) Be, Mg, Ca

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 16.
In which group of the periodic table will the element with atomic number z=17 occur ?
(A) IA
(B) IIIB
(C) VIIB
(D) VIB
Answer:
(C) VIIB

Question 17.
Pnicogens are the elements belonging to the :
(A) 12 group
(B) 13 group
(C) 15 group
(D) 16 group
Answer:
(C) 15 group

Question 18.
5f-subshell is successively filled up in :
(A) actinoids
(B) lanthanoids
(C) trypical metals
(D) normal metal
Answer:
(A) actinoids

Question 19.
In the long form periodic table, the block containing non-metals is:
(A) s
(B) p
(C) d
(D) f
Answer:
(B) p

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 20.
Variable valency is shown by :
(A) typical elements
(B) normal elements
(C) transition elements
(D) none of the above
Answer:
(C) transition eleme is

Question 21.
Which of the following form coloured salts ?
(A) non-metals
(B) metals
(C) p-block elements
(D) transition elements
Answer:
(D) transition elements

Question 22.
Which of the following does not reflect the periodicity of elements :
(A) Bonding behaviour
(B) Electronegativity
(C) Ionisation-potential
(D) Neutron/proton ratio
Answer:
(D) Neutron prolon ratio

Question 23.
Zero group wasjntroduced by
(A) Lother Meyer
(B) Mendeleev
(C) Ramsay
(D) Locker
Answer:
(C) Ramsay

Question 24.
The telluric helix was given by :
(A) Newlands
(B) Lother Meyer
(C) Mendeleev
(D) De Chancourtois
Answer:
(D) De Chancourtois

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 25.
Lithium shows diagonal relationship with :
(A) Ne
(B) Mg
(C) Be
(D) Ce
Answer:
(B) Mg.

Question 26.
The number of elements discovered till date is :
(A) 63
(B) 109
(C) 60
(D) 118
Answer:
(D) 118

Question 27.
At the time of publication of Mendeleev’s periodic table the number of inert gas elements discovered are :
(A) 1
(B) 8
(C) 3
(D) 0
Answer:
(D) 0

Question 28.
How many periods are there in the Mendeleev’s periodic table ?
(A) 7
(B) 10
(C) 6
(D) 14
Answer:
(A) 7

Question 29.
The similarity between the subgroup A and B elements is with respect to their :
(A) physical properties
(B) chemical properties
(C) valency
(D) none
Answer:
(C) Valency

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 30.
Long form of periodic table based on :
(A) atomic number
(B) atomic mass
(C) number of neutrons
(D) none of these
Answer:
(A) atomic number

Question 31.
Which period contains the greatest number of metals?
(A) 1
(B) 2
(C) 3
(D) 4
Answer:
(D) 4

Question 32.
Which of the following elements belongs to the group that includes the most active metals?
(A) Aluminium
(B) Sodium
(C) Iron
(D) Mercury
Answer:
(B) Sodium

Question 33.
At the end of each period the valence shell is
(A) incomplete
(B) half filled
(C) singly occupied
(D) completely filled
Answer:
(D) completely filled

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 34.
Hydrogen is called ?
(A) rogue element
(B) noble element
(C) transuranic element
(D) rare earth element
Answer:
(A) rogue element

Question 35.
Which of the following is a transuranic element ?
(A) Radium
(B) Neptunium
(C) Thorium
(D) Actinium
Answer:
(B) Neptunium

Question 36.
An element in second period whose electron affinity is zero is :
(A) Helium
(B) Argon
(C) Neon
(D) Krypton
Answer:
(C) Neon

Question 37.
Group 17 elements are also called as :
(A) alkali metals
(B) transition metals
(C) chalcogen
(D) halogen
Answer:
(D) halogen

Question 38.
which of the given elements A, B, C, D and E with atomic number 2,3,7,10 and 30 respectively belong to the same period?
(A) A, B, C
(B) B, C, D
(C) A, D
(D) A, C, E
Answer:
(B) B, C, D

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

Question 39.
The correct order of ionization potential is :
(A) Mg > Ar > Si
(B) Mg < Ar < i
(C) Mg > Si > Ar
(D) Mg < Si < Ar
Answer:
(D) Mg < Si < Ar

Question 40.
Which one is not a Dobereiner’s triad?
(A) Li, Na, K
(B) C, Si, Ge
(C) Ca, Sr, Ba
(D) Cl, Br, I
Answer:
(B) C, Si, Ge

Question 41.
Which one of the following is not a transition element?
(A) Fe
(B) Co
(C) Ca
(D) Cr
Answer:
(C) Ca

Question 42.
The atomic number of an element is 19. In modern periodic table, this element is placed in :
(A) First period
(B) Second period
(C) third period
(D) fourth period
Answer:
(D) fourth period

Question 43.
The element, which has zero electron affinity is third period is :
(A) Al
(B) P
(C) Ar
(D) S
Answer:
(C) Ar

Fill in the blanks :

1. The cause of periodicity of elements in the periodic table is that these elements have _______ configuration.
Answer:
similar.

2. The radioactive element among halogens is _______.
Answer:
astatine.

3. AIl the lanthanides and actinides belong to ________ group in the periodic table.
Answer:
3 or IIIB.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

4. Inert gases have the general electronic configuration ________.
Answer:
n s2 sp}6

5. The elements of s and p-blocks are collectively known as _______ elements.
Answer:
representative

6. First I.P. of nitrogen is ______ than that of oxygen.
Answer:
greater.

7. \(\mathbf{N a}^{\oplus}\) ion is _______ in size than Na-atom.
Answer:
smaller.

8. Strong electropositive elements are ______ good.
Answer:
reducing agents.

9. Ca2+ has a smaller ionic radius than K+because it has ______.
Answer:
higher nuclear charge.

10. The ionisation potential of an element ________ on moving from left to right in a period.
Answer:
increases.

11. On Pauling’s electronegativity scale, the element next to F is ______.
Answer:
oxygen.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

12. Transition metal compounds are coloured because of ______.
Answer:
absorption of visible light.

13. Elements of group IA are called ______ metals.
Answer:
alkali.

14. Electronegativity or non-metallic character gradually ______ along a period from left to right.
Answer:
increases.

15. In a period, all the elements have the same number of electronic ______.
Answer:
shells.

16. Atomic size refers to the distance between the centre of nucleus and the ______ shell of an atom.
Answer:
outermost.

17. The vertical columns in which elements of similar physical and chemical properties occur in the periodic table are called _______.
Answer: groups.

18. Atomic number of an element is more ______ than its atomic weight.
Answer:
fundamental.

19. The term ‘periodic’ means _______ of anything at regular intervals.
Answer:
recurrence.

20. The elements belonging to zero group are chemically _______
Answer:
inert.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

21. Hydrogen belongs to the ______ period.
Answer:
1 A (one).

22. Helium belongs to the ______ group.
Answer:
0 (zero).

25. The periodic table is seen to be divided into different horizontal series called _______.
Answer:
periods.

24. The elements in the modern periodic table are arranged in the increasing order of their _______.
Answer:
atomic number.

25. There are _____ elements in the fourth period of the periodic table.
Answer:
18.

26. The energy released when electron is added to a neutral gaseous atom is called ______ of the atom.
Answer:
electron affinity

27. Second period of periodic table contains ________ elements.
Answer:
8

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

28. Halogens are strong ______ agents.
Answer:
Oxidant

29. Along a period from left to right atomic radii ________.
Answer:
decreases

30. Name of a transitional element.
Ans:
copper

31. Across a period the number of ______ electrons increases by 1, while down the group they remain same.
Answer:
valence

32. All inert gases except _______ has 8 electrons in their outermost shell.
Answer:
helium

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

33. The basis of modern periodic table is _______ number.
Answer:
atomic

34. According to the modern periodic law, ________ of elements are a periodic function of their atomic number.
Answer:
properties

35. Group 3 to 12 contains elements known as ________ elements.
Answer:
transition

36. On going down a group in the periodic table, the size of atoms _______.
Answer:
increases

37. The incomplete period in the periodic table is _______.
Answer:
7th period

38. If an element has low tonization energy, it is likely to be _______.
Answer:
metallic

39. The elements in ______ are called alkaline earth metals.
Answer:
Group-2

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

40. The elements in group1 are called _______ metals.
Answer:
alkali

State whether the following statement is True or False : VSA

1. Mendeleev’s eka-silicon was later found to be silicon.
Answer:
False

2. An element with three electron shells and two valence electrons belongs to third period and Group two.
Answer:
True

3. A metal “X” is in the first group of the periodic table. The formula of its oxide is X2O.
Answer:
True

4. All the elements of a particular group in the periodic table have the same number of valence electrons.
Answer:
True

5. On moving from left to right in a period of the periodic table, the size of the atom increases.
Answer:
False

6. Group 17 elements are called rare earth elements.
Answer:
False

7. The modern periodic table was prepared by Niels Bohr.
Answer:
True

8. In Lothar Meyer’s atomic volume versus atomic mass curve, the peaks are occupied by the alkali metals.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.1 Periodic Table and Periodicity of the Properties of Elements

9. On moving from left to right in a period, the electropositive character of elements decreases, but electronegeative character increases.
Answer:
True

10. Lithium, Sodium and Potassium form a Dobereiner’s triad.
Answer:
True

11. Lother Meyer pointed out that atomic volumes of solid elements are periodic functions of their atomic weight.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus can serve as a valuable review tool before exams.

Atomic Nucleus Class 10 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1.
Radioactive disintegration differs from a chemical change in being
(A) a nuclear process
(B) an exothermic process
(C) a sponteneous process
(D) a unimolecular first order reaction
Answer:
(A) a nuclear process

Question 2.
The phenomenon of radioactivity was first discoverd by –
(A) Rutherford
(B) Henry Becquerel
(C) Niels Bohr
(D) Madam curie
Answer:
(D) Modam curie.

Question 3.
a-rays consist of a stream of –
(A) H+
(B) He2+
only electrons
(D) only neutrons
Answer:
(B) He

Question 4.
Which of the following radiations, the one most easily stopped by air is –
(A) X-rays
(B) α-rays
(C) β-rays
(D) γ-rays
Answer:
(A) X-roys

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 5.
γ-rays –
(A) consist of (+) ve particles
(B) are energy waves
(C) are deflected by an electric field
(D) have mass
Answer:
(B) are energy waves

Question 6.
A device used for the measurement of radioactivity is –
(A) mass spectrometer
(B) cyclotron
(C) nuclear reactor
(D) G-M-counter
Answer:
(D) G-M-counter

Question 7.
If a radioactive element is placed in an evacuated container, its rate of disintegration –
(A) will be increased
(B) will be decreased
(C) will change very slightly
(D) will remain unchanged
Answer:
(D) will remain unchanged

Question 8.
Emission of a β-particle by an atom of an element results in the formation of its
(A) isotope
(B) isomer
(C) isobar
(D) isomorph
Answer:
(C) isobar

Question 9.
Which of the following combinations will give the most stable nuclei?
(A) Odd Z and odd N
(B) Even Z and even N
(C) Odd Z and even N
(D) Even Z and odd N
Answer:
(B) Ever Z and even N

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 10.
Stable nuclides cannot be obtained for –
(A) Z = 43, N = 35
(B) Z = 61, Z = 89
(C) A > 209
(D) All of these
Answer:
(D) All of thest

Question 11.
Which of the following nuclei are stable?
(A) \({ }_{28}^{60} \mathrm{Ni}\)
(B) \({ }_6^{11} \mathrm{C}\)
(C) \({ }_92233} \mathrm{U}\)
(D) \({ }_4^{8} \mathrm{Be}\)
Answer:
(D) \({ }_4^{10} \mathrm{Be}\)

Question 12.
Which of the following nuclel is unstable ?
(A) \({ }_5^{10} \mathrm{C}\)
(B) \({ }_7^{14} \mathrm{N}\)
(C) \({ }_8^{16} \mathrm{O}\)
(D) \({ }_4^{10} \mathrm{Be}\)
Answer:
(D) \({ }_4^{10} \mathrm{Be}\)

Question 13.
One becquerel of radioactivity of equal to –
(A) one disintegation/s
(B) two disintegration/s
(C) 6.023 × 1023 disintegration/s
(D) three disintegration/s
Answer:
(A) one disintegation/s

Question 14.
The emission of beta-particles is from-
(A) the valence shell of an atom
(B) the inner shell of an atom
(C) the nucleus due to the nuclear conversion proton → neutron + electron
(D) the nucleus due to the nuclear conversion neutron → proton + electron.
Answer:
(D) the nucleus due to the nuclear conversion neutron → proton + electron.

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 15.
Which of the following processes causes the emission of an x-ray?
(A) Alpha emission
(B) Gamma emissionz`
(C) Positron emission
(D) Electron capture
Answer:
(D) Electron capture

Question 16.
Loss of β-particle is equivalent to –
(A) increase of one proton
(B) decrease of one neutron
(C) combination of both (A) and (B)
(D) None of the above
Answer:
(C) combination of both (A) and (B)

Question 17.
Choose the incorrect one –
(A) 1 curie = 3.7 × 1010 ds-1
(B) 1 rutherford = 106 ds-1
(C) 1 becquerel = 1 ds-1
(D) 1 fermi = 103 ds-1
Answer:
(D) 1 fermi = 103 ds-1

Question 18.
Which of the following is the man-made redioactive disintegration series?
(A) Thorium series
(B) Neptunium series
(C) Uranium series
(D) Actinium series
Answer:
(B) Neptunium series

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 19.
Temperature has no effect on the rate of decay because –
(A) nuclear energies are low
(B) radioactive decay is a statistical process
(C) nuclear energies are very high
(D) radioactive decay follow exponential law
Answer:
(C) nuclear energies are very high

Question 20.
Mark the correct relation-
(A) N0 = N e λt
(B) τ = 1.44 t0.5
(C) N = N0 (\(\frac{1}{2}\))n
(D) t0.5 = λ ln2
Answer:
(D) t0.5 = λ ln2

Question 21.
Which one of the following is not a synthetic elements?
(A) U
(B) Cm
(C) Np
(D) PU
Answer:
(A) U

Question 22.
Choose the natural element among the following –
(A) technetium
(B) neptunium
(C) astatine
(D) uranium
Answer:
(D) uranium

Question 23.
Which is not correctly matched here?
(A) Polonium was discovered by Madam curies
(B) Natural radio activity discovered by Henry Becqueral
(C) Maximum penetration power is of α-rays
(D) γ-rays was discovered by willard
Answer:
(C) Maximum penetration power is of α-rays

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 24.
Positron is the name given to an atom like combination formed between-
(A) a positron and a proton
(B) a positron and a neutron
(C) a positron and α-partical
(D) a positron and an electron
Answer:
(D) a positron and an electron

Question 25.
Which of the following are β – emitters ?
(A) Carbon-14
(B) Cobalt – 60
(C) Tritium – 3
(D) All of these.
Answer:
(D) All of these

Question 26.
Which of the following has highest value for its radioactivity ?
(A) 1 g of Ra
(B) 1 g of Ra so4
(C) 1 g of Ra Br2
(D) All of the above have same value
Answer:
(A) 1 g of Ra

Question 27.
Which of the following are α-emitters ?
(A) Helium-5
(B) Tritium
(C) Polonium-212
(D) None of these
Answer:
(C) Polonium-212

Question 28.
In radioactive decay, the emitted electrons come from the-
(A) innermost shell of the atom
(B) outermost shell of the atom
(C) K-shell of an atom
(D) decay neutrons in the nucleus.
Answer:
(D) decay neutrons in the nucleus.

Question 29.
Which emits b-particle?
(A) \({ }_1^3 \mathrm{H}\)
(B) \({ }_6^{14} \mathrm{C}\)
(C) [\({ }_{19}^{40} \mathrm{~K}\)
(D) All of these.
Answer:
(D) All of these.

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 30.
\({ }_1^3 \mathrm{Al}\) is a stable isotope. It is expected to disintegrate by-
(A) α-emission
(B) β-emission
(C) β+-emission
(D) proton emission
Answer:
(B) β-emission

Question 31.
Of the following which is not used as a moderator in a nuclear reactor?
(A) Heavy water
(B) Graphite
(C) Beryllium
(D) Sodium
Answer:
(D) Sodium

Question 32.
Control rods used in the nuclear reactor are made of-
(A) nickel
(B) graphite
(C) iron
(D) cadmium
Answer:
(D) cadmium

Question 33.
The moderator used in atomic pile is-
(A) heavy water
(B) uranium
(C) cadmium
(D) iron
Answer:
(A) heavy water

Question 34.
Control rods of nuclear reactor are made up of-
(A) Cd
(B) copper
(C) diamond
(D) graplite
Answer:
(A) Cd

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 35.
In a nuclear reactor, heavy water is used-
(A) to provide high speed neutrons
(B) to increase the speed of neutrons
(C) to capture neutrons produced by nuclear fission
(D) to transfer the heat from the nuclear reactor
Answer:
(D) to transfer the heat from the nuclear reactor

Question 36.
Near nuclear reactor there is-
(A) large neutron flux
(B) large proton flux
(C) large γ-ray flux
(D) large particles flux
Answer:
(A) large neutron flux

Question 37.
Which of the following isotopes is used in establishing the reaction mechanism of photosynthesis in plants?
(A) \({ }_6^{12} \mathrm{C}\)
(B) \({ }_6^{13} \mathrm{C}\)
(C) \({ }_6^{14} \mathrm{C}\)
(D) \({ }_1^{2} \mathrm{H}\)
Answer:
(C) \({ }_6^{14} \mathrm{C}\)

Question 38.
Which of the following radioactive elements is soluble in water?
(A) Radium
(B) Radon
(C) Technetium
(D) Tritium
Answer:
(B) Radon

Question 39.
Decrease in atomic number is not observed during-
(A) α-emission
(B) β-emission
(C) positron
(D) electron capture
Answer:
(B) β-emission

Question 40.
The relative penetrating power of α, β, γ and neutron (n) follows the order-
(A) α > β > γ > n
(B) n > γ > β > α
(C) β > α > n > γ
(D) None of these
Answer:
(B) n > γ > β > α

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 41.
Which of the following nuclear reactions will generate an isotope?
(A) Neutron particle emission
(B) Positron emission
(C) α-particle emission
(D) β-particle emission
Answer:
(A) Neutron particle emission

Question 42.
Identify the nuclear reaction that differs from the rest-
(A) positron emission
(B) K-capture
(C) β-decay
(D) γ-decay
Answer:
(D) γ-decay

Question 43.
What is the order of reaction of the decay of 235{ _{92 U ?
(A) Zero
(B) first
(C) second
(D) third
Answer:
(B) first

Question 44.
Which of the following has maximum n / P ratio ?
(A) \({ }^{16} \mathrm{Ne}\)
(B) \({ }^{16} \mathrm{O}\)
(C) \({ }^{16} \mathrm{F}\)
(D) \({ }^{16} \mathrm{N}\)
Answer:
(D) \({ }^{16} \mathrm{N}\)

Question 45.
The half life of a radio isotope depends upon-
(A) the amount of isotope
(B) the temperature
(C) the pressure
(D) none of the above
Answer:
(D) none of the above

Question 46.
Which of the following has magic number of protons and neutrons?
(A) \({ }_8^{17} \mathrm{O}\)
(B) \({ }_13^{27} \mathrm{Al}\)
(C) \({ }_9^{17} \mathrm{Al}\)
(D) \({ }_40^{40} \mathrm{Al}\)
Answer:
(D) \({ }_40^{40} \mathrm{Al}\)

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 47.
India conducted an underground nuclear test at-
(A) Tarapur
(B) Narora
(C) Pokhran
(D) Pushkar
Answer:
(D) Pokhran

Question 48.
Positron has mass equal to –
(A) eletron
(B) α-particle
(C) proton
(D) deutron
Answer:
(A) elecron

Question 49.
\({ }_1^1 \mathrm{H}\) + \({ }_1^3 \mathrm{H}\) (B) \({ }_2^4 \mathrm{He}\) represents –
(A) β-decay
(B) fusion
(C) fission
(D) d-decay
Answer:
(B) fusion

Question 50.
Choose the element which is not radioactive-
(A) Cm
(B) No
(C) Mo
(D) Md
Answer:
(C) Mo

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 51.
Who discovered radioactivity :
(A) Bacquerel
(B) Madam curie
(c) Peary curie
(D) Ruther ford
Answer:
(A) Bacquerel

Question 52.
Which of the following rays has higher penetrating power ?
(A) sun ray
(B) β-ray
(c) α-ray
(D) γ-ray
Answer:
(D) γ-ray

Question 53.
Which ray is negatively charged ?
(A) α-ray
(B) β-ray
(C) γ-ray
(D) x-ray
Answer:
(B) β-ray

Question 54.
Due to emission of a β-particle the mass of the daughter element :
(A) Increased by one unit
(B) Decreased by one unit
(C) Remains the same
(D) Decreased by two unit
Answer:
(C) Remains the same

Question 55.
Binding energy is :
(A) Bonding between two atoms
(B) Fission of a covalent bond
(C) Binding among the nucleons in nucleus
(D) None of these
Answer:
(C) Binding among the nucleons in nucleus

Question 56.
Nuclear fission is initiated by :
(A) slow neutron
(B) fast neutron
(C) by proton
(D) by α-particle
Answer:
(A) slow neutron

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 57.
Nuclear energy is :
(A) renewable
(B) not renewable
(C) sometime renewable
(D) it is a matter of debate
Answer:
(B) not renewable

Question 58.
The radioactive isotope used in atom bomb is :
(A) Ra-226
(B) U-238
(C) C-14
(D) U-235
Answer:
(D) U-235

Question 59.
Source of energy of sun is :
(A) Fission reaction
(B) Fusion reaction
(C) Spalation reaction
(D) None of these
Answer:
(B) Fusion reaction

Question 60.
Which nuclear decay emission consists of energy only?
(A) alpha particle
(B) beta particle
(C) gamma radiation
(D) positron emission
Answer:
(C) gamma radiation

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 61.
Which of the following is the correct order of ionising power for α β, and γ ravs?
(A) α > β > γ
(B) α > γ > β
(C) γ > β > α
(D) β > α > γ
Answer:
(A) α > β > γ

Question 62.
Electromagnetic wave among the radloactive rays is :
(A) α-rays
(B) β-rays
(C) γ-rays
(D) cathode rays
Answer:
(c) γ-rays

Question 63.
Which one among the following nuclet has the lowest n:p ratio?
(A) Hydrogen
(B) Deuterium
(C) Tritium
(D) Helium
Answer:
(A) Hydrogen

Question 64.
Number of neutrons in a α-particle is :
(A) 1
(B) 2
(C) 3
(D) 4
Answer:
(B) 2

Question 65.
Identify the wrong statement :
(A) Radioactivity is a nuclear phenomena
(B) Emission of radioactive rays depends on the number of valence electrons
(C) Radioactivity was first discovered by Becquerel
(D) Three types of radiations are emitted during radiation from a radioactive element.
Answer:
(B) Emission of radioactive rays depends on the number of valence electrons.

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

Question 66.
Atom bomb was first used in war during
(A) World war II
(B) Gulf war
(C) Cuban war
(D) Indo-Pak war in 1965
Answer:
(A) World war II

Question 67.
Nuclear fission is initiated by :
(A) slow neutron
(B) proton
(C) fast neutron
(D) α particle
Answer:
(A) slow neutron

Question 68.
At around what mass number is the binding energy per nucleon greatest?
(A) 26
(B) 58
(C) 111
(D) 235
Answer:
(B) 58

Question 69.
The nuclear reaction \({ }_1^2 \mathrm{H}\) + \({ }_1^2 \mathrm{H}\) → \({ }_2^4 \mathrm{He}\) is called :
(A) fission reaction
(B) fusion reaction
(C) chain reaction
(D) thermal reaction
Answer:
(B) fusion reaction

Fill in the blanks :

1. Due to the large mass, a-particles possess large ______.
Answer:
Kinetic energy.

2. β-particles are _______ charged.
Answer:
negatively

3. γ-rays are _______.
Answer:
neutral

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

4. γ-rays have least effect on _______.
Answer:
photographic plates

5. Isotopes of the same element possess same number of _____.
Answer:
protons

6. Accroding to Einstein’s equation, the relationship between mass and energy can be written as ______.
Answer:
E = m c2

7. Atoms of the same element having same atomic number but different atomic masses are called ______.
Answer:
isotopes

8. Atoms of the different elements paossessing same mass number are called _____.
Answer:
Isobars.

9. Isotones are the nuclides having same number of ______.
Answer:
neutrons.

10. Atoms of the same element possessing identical atomic mass but differing in half-life period are called ______.
Answer:
nuclear isomers.

11. The phenomenon of spontaneous emission of invisible radiation is called ______
Answer:
radioactivity

12. β-particles are nothing but ______ moving with high speeds.
Answer:
electrons

13. Electrically neutral electromagnetic waves ejected during radioactive disintegration are called ______.
Answer:
γ-rays.

14. The phenomenon in which a stable nuclide is converted artificially into a radioactive substance is called _____.
Answer:
artificial radioactivity.

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

15. The speed of γ-rays is ______ speed of light.
Answer:
equal to

16. Atom bomb is based on nuclear _______ reaction.
Answer:
fission

17. Hydrogen bomb is based on nuclear _______ reaction.
Answer:
fusion

18. Source of the energy of the Sun is ______.
Answer:
fusion

19. The time taken for decay of half the initial amount of a radioactive nuclide is called _____.
Answer:
half-life period.

20. The energy required to separate a nucleus into its individual nucleons is known as _______.
Answer:
binding energy

21. The number of neutrons in a radioactive isotope of hydrogen is _____.
Answer:
2

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

22. The rate of disintegration of active nucleus is known as ______.
Answer:activity

23. \({ }_1^2 \mathrm{H}+{ }_1^3 \mathrm{H} \rightarrow{ }_2^4 \mathrm{He}\) is a _____ reaction.
Answer:
fusion

24. The mass defect in the formation of boron atom \(\frac{1}{5}\) B is 0.0810 amu. The binding energy per nucleon is ______.
Answer:
6.86 MeV

25. \({ }_7^{14} \mathrm{~N}+{ }_0^1 \mathrm{n}\) → ________ + \({ }_7^{14} \mathrm{H}\)
Answer:
{ _6^{-14 C

26. A radioactive nucleus decay emitting one α and two β particles, the daughter nucleus is _______ of the parent.
Answer:
isotope.

27. Particles having energy of several hundred MeV are known as _______.
Answer:
Superfast particles

28. An element \({ }_{\mathbf{Z}}^{\mathbf{A}} \mathbf{M}\) undergoes α-emission followed by two successive β-emissions. The element formed is _______.
Answer:
\(\mathrm{A}_z^{-4} \mathrm{M}\)

29. The end products in the natural disintegration series are stable isotopes of _____.
Answer:
lead

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

30. One curie of activity is equal to _______ disintegrations per second.
Answer:
3.7 × 1010

31. The energy equivalent to 1 amu is ______ MeV.
Answer:
931.5

32. The density of the nucleus is of the order of ______ g/cm3.
Answer:
1014

33. The difference between the total mass of the particles present in the nucleus of a nuclide and its real mass is called ______.
Answer:
mass defect

34. In exoergic reaction, the total mass of the products is _______ than the total mass of the reactants.
Answer:
less.

35. _______ is the inventor of neutron.
Answer:
J. Chadwick.

36. N2O and CO2 are the examples of ________.
Answer:
isosters

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

37. Magic numbers are 2, 8, 20, 50, 82 and ______.
Answer:
126

38. Radioactivity was proposed by ______.
Answer:
Madam curie.

39. Measurement of radioactivity is done by ______.
Answer:
Geiger-Muller counter.

40. The process of transforming one element into other is known as _______.
Answer:
alchemy.

41. Radioactivity was discovered by _______.
Answer:
Becquerel

42. Charge of an α-particle is _______.
Answer:
+2

43. β – particles are emitted from the _______ of the atom.
Answer:
nucleus.

44. \({ }^{60} \mathrm{C}_0\) isotope is used for the treatment of ______.
Answer:
cancer

45. \({ }^{226}{ }_{8 R} R a\) is a _______ element.
Answer:
radioactive

46. Bombardment of one U-235 with one neutron producer ______ neutrons.
Answer:
3

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

47. chernobyl located in _______.
Answer:
ukraine

48. One gram U-235 generates ________ kW/h electric energy.
Answer:
20,000

49. Fusion reaction occurs at _______ temperature.
Answer:
106 K.

50. The inert gas present in each series is ________.
Answer:
Radon

51. The first radioactive element discovered was __________.
Answer:
uranium

52. In transformation series, radioactivity finally ceases with a a stable __________ isotope as the end product.
Answer:
lead

53. __________ is preceded by a fission reaction.
Answer:
Fusion

54. In a nuclear reactor, the part which consists of the moderator and fuel rods is known as _________.
Answer:
reactor core

55. ‘Atom bomb’ utilizes the ___________ reaction.
Answer:
fission

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

56. According to theory of relativity, mass can be converted to __________ and vice versa.
Answer:
energy

57. Natural uranium with extra U-235 added into it is called ___________.
Answer:
enriched uranium

58. The name of the aeroplane which dropped atom bomb on Hiroshima is ___________.
Answer:
Enola Gay

Q59. On an average ____________ neutrons are produced per each fission.
Answer:
2.5

State whether the following statement is True or False : VSA

1. Radioactivity depends on the number of electrons in the valence shell.
Answer:
False

2. The instability of nucleus in radioactive atoms is caused by the ratio of neutrons and protons in the nucleus.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

3. Radioactivity is a nuclear phenomena.
Answer:
True

4. Due to emission of a beta particle, mass number of the daughter element is decreased by 1 unit.
Answer:
False

5. When metallic radium is converted to radium chloride, it shows a change in the property of radioactivity.
Answer:
False

6. Radioactive tracer technique is used by researchers and medical practitioners.
Answer:
True

7. Fusion is basically just opposite to fission.
Answer:
True

8. Binding energy owes its origin to mass defect.
Answer:
True

9. Fission reaction releases a large amount of energy.
Answer:
True

10. Inside the thermal reactor, the control rods slow down the neutrons to stimulate further fission.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 7 Atomic Nucleus

11. Nuclear reactor is used to safely convert nuclear energy into electricity.
Answer:
True

12. Atom bomb is based on principles of thermonuclear fusion.
Answer:
False

13. Energy of the stars is attributed to nuclear fission reactions.
Answer:
False

14. The nuclear disaster in Fukushima was initiated after a Tsunami.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy can serve as a valuable review tool before exams.

Metallurgy Class 10 WBBSE MCQ Questions

Multiple choice questions (MCQ) :

Question 1.
Most of the plants contain :
(A) Iron
(B) Zinc
(C) Sodium
(D) Potassium
Answer:
(D) Potassium.

Question 2.
Malachite is mineral containing :
(A) Magnesium
(B) Aluminium
(C) Copper
(D) Tin
Answer:
(C) Copper

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 3.
The most electropositive alkali metal is :
(A) Li
(B) Na
(C) K
(D) Cs
Answer:
(D) Cs.

Question 4.
Calcium is extracted by the electrolysis of :
(A) CaCl2 solution
(B) CaSO4 solution
(C) fused CaCl2
(D) fused Ca3(PO4)2
Answer:
(C) fused CaCl2

Question 5.
Which of the following is not the ore of magnesium ?
(A) Carnallite
(B) Dolomite
(C) Gypsum
(D) Magnesite
Answer:
(C) Gypsum.

Question 6.
Magnesium is isolated by the electrolysis of :
(A) fused MgCl2
(B) MgCl2 solution
(C) MgSO4 solution
(D) MgO dissolved in MgCl2
Answer:
(A) fused MgCl2

Question 7.
Dolomite is an ore of magnesium and it is :
(A) MgCO3
(B) MgCO3, CaCO3
(C) MgCl2, KCl, 6H2O
(D) None of these
Answer:
(B) MgCO3, CaCO3

Question 8.
Carnallite is an ore of magnesium and it is :
(A) K2SO4, MgSO4, MgCl2,6H2O
(B) MgSO4, H2O
(C) MgCl2,KCl, 6H2O
(D) None of these
Answer:
(C) MgCl2,KCl, 6H2O

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 9.
Calcium oxide is also called : ……………….
(A) milk of lime
(B) quick lime
(C) lime stone
(D) slaked lime
Answer:
(B) quick lime

Question 10.
One of the important uses of quick lime is :
(A) in bleaching silk
(B) in drying gases and alcohol
(C) as a purgative
(D) in dyeing cotton
Answer:
(B) in drying gases and alcohol

Question 11.
Heating of pyrites to remove sulphur is called as:
(A) Roasting
(B) Calcination
(C) Smeting
(D) Fluxing
Answer:
(A) Roasting.

Question 12.
The element which is some times found in native state is :
(A) Al
(B) Cu
(C) Fe
(D) Mg
Answer:
(B) Cu

Question 13.
The fluorspar is :
(A) CaSO4
(B) BaSO4
(C) CaF2
(D) CaCO3
Answer:
(C) CaF2

Question 14.
Which of the following is not the ore of calcium ?
(A) Gypsum
(B) Lime stone
(C) Dolomite
(D) Carnallite
Answer:
(D) Carnallite.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 15.
The chief ore of aluminium is :
(A) Feldspar
(B) Bauxite
(C) Mica
(D) Kaolin
Answer:
(B) Bawxite.

Question 16.
Baeyer’s process is used for the purification of :
(A) Boron
(B) Aluminium
(C) Titanium
(D) None of these
Answer:
(B) Aluminium

Question 17.
Alumina is :
(A) acidic
(B) basic
(C) neutral
(D) amphoteric
Answer:
(D) amphoteric

Question 18.
Pin iron is also called :
(A) Wrought iron
(B) Cast iron
(C) Steel
(D) Stainless steel
Answer:
(B) Cast iron

Question 19.
Blast furnace is used in the metallurgy of :
(A) Aluminium
(B) Gold
(C) Iron
(D) Silver
Answer:
(C) Iron

Question 20.
Haematie is :
(A) Fe3 O4
(B) Fe3 O3
(C) Fe2 O3 Cao
(D) None of these.
Answer:
(B) FeO3

Question 21.
One of the following is not the ore of copper :
(A) Copper glance
(B) Azurite
(C) Malachite
(D) Corrundum
Answer:
(D) Corrundum

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 22.
Froth floatation process is used in the metallurgy of :
(A) chloride ores
(B) sulphide ores
(C) oxide ores
(D) amalgam
Answer:
(B) sulphide ores

Question 23.
Which of the following elements is present in haemoglobin ?
(A) Mg
(B) Fe
(C) Cu
(D) Zn
Answer:
(B) Fe

Question 24.
Metal present in insulin is :
(A) Copper
(B) Iron
(C) Zinc
(D) Magnesium
Answer:
(C) Zinc.

Question 25.
In electrorefining of copper, some gold is deposited as :
(A) Anode mud
(B) Cathode mud
(C) Cathode
(D) Electrolyte
Answer:
(A) Anode mud

Question 26.
In blast furnace, the highest temperature is in :
(A) reduction zone
(B) slag formation zone
(C) fusion zone
(D) combustion zone
Answer:
(D) combustion zone

Question 27.
Which is the more pure iron ?
(A) cast iron
(B) pig iron
(C) steel
(D) wrought iron
Answer:
(D) Wrought iron

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 28.
Which is extensively used for making aeroplane body ?
(A) Zn
(B) Cu
(C) Fe
(D) Al
Answer:
(D) Al

Question 29.
Which alloy does not contain copper ?
(A) mistch metal
(B) bell metal
(C) german silver
(D) delta metal
Answer:
(A) Mistch metal

Question 30.
Percentage of silver in german silver is :
(A) 55
(B) 0
(C) 0.5
(D) 24
Answer:
(B) 0

Question 31.
Which is not mineral ?
(A) sulphur
(B) haematite
(C) petroleum
(D) zincite
Answer:
(C) Petroleum

Question 32.
Electrolysis of molten NaCl produces Na and Cl, because :
(A) Na is oxidised B
(B) C is oxidised
(C) Both are oxidised
(D) none of these are oxidised or reduced
Answer:
(B) Cl is Oxidised

Question 33.
In thermite process which is used as reducing agent ?
(A) carbon
(B) iron
(C) aluminium
(D) zinc
Answer:
(C) aluminium

Question 34.
In cathodic protection of iron which is acting as anode?
(A) iron
(B) magnesium
(C) platinum
(D) H2O
Answer:
(B) magnesium

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 35.
The green patches form on the surface of copper is :
(A) CuSO4
(B) CU(OH)2
(C) CuO
(D) CuSO4 . 3 Cu(OH)2
Answer:
(D) CuSO. 3 Cu(OH)2

Question 36.
Which alloy among the following Is used In electrical fittings?
(A) German silver
(B) Brass
(C) Alnico
(D) Bell metal
Answer:
(B) Brass

Question 37.
What should be used to remove the green patties formed on the copper surface?
(A) detergent water
(B) lemon juice
(C) sand paper
(D) washing soda
Answer:
(B) lemon juice

Question 38.
Aluminium is responsible for
(A) Wilson’s disease
(B) Hepatitis-B
(C) Alzheimer’s disease
(D) Perkinson’s disease
Answer:
(C) Alzheîmer’s disease

Question 39.
The metal which can be extracted by simply heating the cinnabar ore mains: –
(A) mercury
(B) zinc
(C) copper
(D) iron
Answer:
(A) mercury

Question 40.
What are the constituents of alloy solder?
(A) Lead, Zinc
(B) Copper, tin
(C) Lead, tin
(D) Copper, Zinc
Answer:
(C) Lead, tin

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

Question 41.
Which metal is extracted by the electrolytic reduction of their molten chlorides or oxides?
(A) sodium
(B) iron
(C) zinc
(D) copper
Answer:
(A) sodium

Question 42.
Two metals which can be extracted by heating their suiphides in air,
(A) Na & Cu
(B) Cu & Ai
(C) K & Zn
(D) Hg & Cu
Answer:
(D) Hg & Cu

Question 43.
Which ore is used as a reducing agent in thermite process?
(A) Chromium
(B) manganese
(C) aluminium
(D) iron
Answer:
(C) aluminium

Question 44.
Food cans are coated with tin and not with zinc because
(A) Zinc has higher melting point than tin
(B) Zinc is costlier than tin
(C) Zinc is more reactive than tin
(D) Zinc is less reactive than tin
Answer:
(C) Zinc is more reactive than tin

Question 45.
Which of the following methods is suitable for preventing an iron fry- 4ng pan from rusting?
(A) Applying grease
(B) Applying paint
(C) Applying a coating of zinc
(D) All of the above
Answer:
(D) All of the above

Question 46.
Activity of the metals (in the reactivity series) decreases in the order:
(A) K > Al > Zn > Au
(B) K > AI > Au > Zn
(C) Au < K < Zn < AI
(D) K > Zn > Au >Al
Answer:
(A) K > Al > Zn > Au

Fill in the Blanks:

1. _______ disease occurs due to abnormal copper metabolism.
Answer:
wilson’s

2. When exposed to moist air for a prolonged time, _______ coloured patches are formed on copper surface.
Answer:
green

3. A shining aluminium surface gradually loses Its shine due to formation of ____
Answer:
aluminium oxide

4. Brass Is an alloy of copper and ____
Answer:
zinc

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

5. Constantan is an alloy of copper and ____
Answer:
nickel

6. Rusting is faster in presence of _______ ion.
Answer:
chloride

7. Galvanization is the process of applying a thin layer of _______ on ion objects.
Answer:
zinc

8. Metals of _______ activity are extracted by reduction of their oxide with carbon.
Answer:
moderate

9. Haematite is an ore of _______
Answer:
aluminium

10. Duralumin is an alloy of _______
Answer:
aluminium

State whether the following statement is True or False :

1. Aluminium is responsible for Alzheimer’s disease.
Answer:
True

2. Rust is actually hydrated iron oxide.
Answer:
True

3. Cooking utensils made up of aluminium are often anodized
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

4. Corrosion of iron can be modeled as a short-circuited electrochemical ceil.
Answer:
True

5. Rusting requires either the presence of air or presence of water.
Answer:
False

6. Lemon juice should not be kept in a copper vessel.
Answer:
True

7. Mercury is extracted by heating its oxide.
Answer:
True

8. In reactivity series of metals, sodium is placed higher than iron.
Answer:
True

9. Stainless steel has a very low carbon content.
Answer:
True

10. Calamine is an ore of calcium.
Answer:
False

11. Bauxite is an ore of zinc.
Answer:
false

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.5 Metallurgy

12. All the ores are minerals but not all the minerals are ores.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry can serve as a valuable review tool before exams.

Organic Chemistry Class 10 WBBSE MCQ Questions

Question 1.
CnH2n + 2 is general formula of ________
(A) Alkenes
(B) Alkynes
(C) Alkanes
(D) Ring
Answer:
(C) Alkanes

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 2.
Aliphatic hydrocarbons with double bond : ________
(A) are saturated
(B) generally add bromine
(C) belong to the acetylene family group
(D) belong to the paraffin
Answer:
(B) generally add bromine

Question3.
When sodium acetate is heated with soda lime, the reaction is called: ________
(A) Dehydration
(B) Decarboxylation
(C) Dehydrogenation
(D) Dehydrohalogenation
Answer:
(B) Decarboxylation

Question 4.
Ethylene can be prepared by reacting ethyl bromide with : ________
(A) Alcoholic KOH
(B) Amoniacal AgNO3
(C) Acidified KMnO4
(D) C and H2SO4
Answer:
(A) Alcoholic KOH

Question 5.
The product obtained when chloroform is treated with silver powder is: ________
Ethylene
ethane
Acetylene
Methane
Answer:
Acetylene

Question 6.
A metallic carbide on treatment with water gives a colourless gas which burns readily in air and gives a precipitate with ammoniacal silver nitrate. The gas is : ________
(A) Methane
(B) Ethane
(C) Ethylene
(D) Acetylene
Answer:
(D) Acetylene

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 7.
A gas decolourises bromine in CCl2 and forms a precipitate with ammoniacal silver nitrate. The gas is :
(A) Acetylene
(B) Ethylene
(C) Methane
(D) Ethane
Answer:
(B) Ethylene

Question 8.
The LHCC bond angle in ethylene is : ________
(A) 90°
(B) 120°
(C) 109° 28’
(D) 180°
Answer:
(B) 120°

Question 9.
Saturated hydrocarbons mainly undergo : ________
(A) Addition reactions
(B) Substitution reactions
(C) Elimination reaction
(D) Polymerisation
Answer:
(B) Substitution reactions

Question 10
Which of the following bonds is strongest?
WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry 1
Answer:
(C)

Question 11.
The reaction
WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry 2 is called : ________
(A) Kolbe’s reaction
(B) Annizzaro’s reaction
(C) Sabatier and Senderen’s reaction
(D) Clemmensen reaction
Answer:
(C) Sabatier and senderen’s reaction

Question 12.
Both methane and ethane may be obtained in one step reaction from ________
(A) C2H4
(B) CH3I
(C) CH3OH
(D) C2H5OH
Answer:
(B) CH3I

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 13.
Which of the following liberates methane on treatment with water ?
(A) Silicon carbide
(B) Calcium carbide
(C) Aluminium carbide
(D) Iron carbide
Answer:
(C) Aluminium carbide

Question 14.
On heating sodium acetate with sodium hydroxide, the gas evolved will be : ________
(A) Acetylene
(B) Ethane
(C) Methane
(D) Ethylene
Answer:
(C) Methane

Question 15.
A compound having a triple bond is more reactive because : ________
(A) there is a strain in the molecule
(B) valency of hydrogen is different
(C) electron density is higher
(D) none
Answer:
(C) electron density is higher.

Question 16.
Acidic hydrogen is present in : ________
(A) Ethyne
(B) Ehene
(C) Benzene
(D) Ethane
Answer:
(A) Ethyne

Question 17.
Final product of the oxidation of hydrocarbon is : ________
(A) CO2 and H2O
(B) Alcohol
(C) Acid
(D) Aldehyde
Answer:
(A) COand H2O

Question 18.
General formula for alkenes is : ________
(A) CnH2n
(B) CnH2n+1
(C) CnH2n-1
(D) C2nH2n
Answer:
(A) CnH2n

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 19.
Marsh gas mainly contains : ________
(A) H2S
(B) CO
(C) CH4
(D) C2H2
Answer:
(C) CH4

Question 20.
Which of the following gases is used in welding ?
(A) C2H4
(B) C2H2
(C) CH4
(D) C2H6
Answer:
(B) C2H2

Question 21.
Which hydrocarbon is used in making printer’s ink and paints ?
(A) CH4
(B) C2H6
(C)  C2H4
(D)  C2H2
Answer:
(A) CH4

Question 22.
The sugar which is stored in the liver to act as reserve food is : ________
(A) Glycogen
(B) Glucose
(C) Sucrose
(D) Fructose
Answer:
(A) Glycogen

Question 23.
Sweetest among all the sugar is : ________
(A) Fructose
(B) Glucose
(C) Sucrose
(D) Lactose
Answer:
(A) Fructose

Question 24.
The main structural feature of protein is : ________
(A) Ether linkage
(B) Peptide linkage
(C) Ester linkage
(D) All the above
Answer:
(B) Peptide linkage

Question 25.
Which of the following is protein ?
(A) Terry cotton
(B) Natural silk
(C) Nylon
(D) Rayon
Answer:
(B) Natural silk.

Question 26.
Which of the following contains nitrogen ?
(A) Fats
(B) Proteins
(C) Carbohydrate
(D) None
Answer:
(B) Proteins

Question 27.
Which of the following is an organic compound ?
(A) urea
(B) NaHCO3
(C) CO4
(D) NH4 CNS
Answer:
(A) urea

Question 28.
Organic compound are:________
(A) high melting
(B) low meffing
(C) soluble in water
(D) conducts electricity in molten state
Answer:
(B) low melting

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 29.
Tetravalence of carbon is proposed by: ________
(A) Wohler
(B) Lavoisier
(C) Kekule
(D) Vant Hoff
Answer:
(C) Kekule

Question 30.
Tetrahedral model of carbon compounds proposed by: ________
(A) Kekule
(B) Rutherford
(C) Wohier
(D) Vant Hoff
Answer:
(D) Vont Hoff

Question 31.
The number of covalent bonds present in ethane is : ________
(A) 4
(B) 6
(C) 7
(D) 9
Answer:
(C) 7

Question 32.
Which molecule has tetrahedral geometry? ________
(A) methane
(B) ethylene
(C) acetylene
(D) carbon dioxide
Answer:
(A) methane

Question 33.
Which does not react with metallic sodium?
(A) methyl alcohol
(B) ethyl alcohol
(C) acetic acid
(D) dimethyl ether
Answer:
(D) Dmethyt ether

Question 34.
How many positional isomers are possible with the molecular formula C3H10?
(A) 1
(B) 2
(C) 3
(D) 4
Answer:
(C) 2

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 35.
How many functional isomers are possible with molecular formula C3H8O?
(A) 1
(B) 3
(C) 2
(D) 4
Answer:
(C) 2

Question 36.
IUPAC name of CH3 CH2 CH2 OH is:
(A) propan-1-oI
(B) n-propanol
(C) isopropanol
(D) propyl alcohol
Answer:
(A) Propon-I-ol

Question 37.
IUPAC name of Formaldehyde Is:
(A) Butanal
(B) Propanal
(C) Ethanal
(D) Methanal
Answer:
(D) Methanal

Question 38.
The total number of different carbon chains that five carbon atoms form in alkane is:
(A) 5
(B) 4
(C) 3
(D) 2
Answer:
(C) 3

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

Question 39.
The IUPAC name of the hydrocarbon present in rectified spirit is :
(A) methanol
(B) ethanol
(C) trichioromethane
(D) ethanai
Answer:
(B) ethanol

Question 40.
Which of the following functional group is present in vinegar?
(A) -CHO
(B) C=O
(C) -COOH
(D) -OH
Answer:
(C) -COOH

Question 41.
Which of the following can damage optic nerve?
(A) acetic acid
(B) ethyl alcohol
(C) acetone
(D) methanol
Answer:
(D) methanol

Question 42.
Which one of the following is not a polymer?
(A) LPG
(B) Jute
(C) PVC
(D) PET
Answer:
(A) LPG

Question 43.
Urea was synthesized by wohier from ………
(A) ammonia and carbon monoxide
(B) ammonium cyanate
(C) ammonium thiocyanate
(D) ammonium chloride and CO2
Answer:
(B) ammonium cyanate

Question 44.
Identify the wrong statement
(A) Organic compounds have low m.p. and b.p.
(B) Organic Compounds are Soluble in solvent having high dielectric constant.
(C) Most organic compounds are do not conduct electricity
(D) Most of the organic compounds are liquid or gaseous under ordinary temperature and pressure.
Answer:
(b) Organic Compounds are soluble in solvent having high dielectric constant.

Question 45.
Organic compounds are generally
(A) Soluble in water
(B) insoluble in water
(C) ionize in water
(D) hydrolyze in water
Answer:
(B) insoluble in water

Question 46.
The biggest source of methane is …………….
(A) Synthesis gas
(B) natural gas
(C) nerve gas
(D) LPG
Answer:
(B) natural gas

Question 47.
Chlorine reacts with saturated hydrocarbons at room temperature in the
(A) presence of sunlight
(B) absence of sunlight
(C) presence of moisture
(D) presence of an acid catalyst
Answer:
(A) presence of sunlight

Fill in the Blanks:

1. …………. is the abbreviation of polyvinyl chloride.
Answer:
PVC.

2. The monomer of …………. is tetrafluoroethene.
Answer:
teflon.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

3. …………. is a large molecule made up of many similar units of small molecules.
Answer:
Polymer.

4. The compound bearing the monovalent functional group – CHO are ………….
Answer:
aldehydes.

5. Alkynes are hydrocarbons where at least two carbon atoms combine with a …………. bond.
Answer:
triple.

6. The function group of organic acid is ………….
Answer:
– COOH

7. The functional group of …………. is -NH.
Answer:
amines.

8. Hydrocarbons in which at least two carbon atoms join with a double bond are called ………….
Answer:
alkenes.

9. Catenation is the property where a large number of …………. atoms link together to form large organic molecules.
Answer:
carbon.

10. Proteins contain various kinds of …………. acids.
Answer:
amino

11. RNA is the abbreviation for…………. acid.
Answer:
ribonucleic.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

12. …………. is a complex organic compound responsible for reproduction and maintaining heredity.
Answer:
Gene.

13. …………. and proteins are the polymerisation products of amino acids.
Answer:
Polypeptides.

14. Amino acids are the end products of the digestion of ………….
Answer:
proteins.

15. Polypeptide chains are the chains of ………….
Answer:
polymers of amino acids.

16. Sucrose on hydrolysis give one …………. and one fructose molecule.
Answer:
glucose.

17. Starch is …………. saccharide.
Answer:
poly.

18. Carbohydrates containing a keto group are called ………….
Answer:
ketoses.

19. Vitamin C is soluble in ………….
Answer:
water.

20. Globular proteins me …………. in water.
Answer:
soluble.

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

21. The carbon chains in alkenes are ………….
Answer: zig-zag.

22. Hydrocarbons are more soluble in …………. solvents.
Answer:
non-polar.

23. Ethane on combustion produces ………….
Answer:
Carbon dioxide and water.

24. AlC evolves …………. when treated with water.
Answer:
methane.

25. Halogenation of alkanes does not occur in ………………….
Answer: dark.

26. Wurtz reaction is used for the preparation of ………………….
Answer:
alkanes.

27. Melting point of organic compounds are …………………. than of inorganiccompounds.
Answer:
lower.

28. Organic compounds are …………………. and inorganic compounds are…………………..
Answer:
covalent, electrovalent

29. Kekule proposed C is …………………. and Vant Hoff proves C is ………………….
Answer:
tetravalent, covalent

30. The simplest alkane is …………………..
Answer:
methane

31………………… is the active ingredient of all alcoholic drinks.
Answer:
Ethanol

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

32. The first organic compound synthesized in the laboratory is ……..
Answer:
urea

33. H – C – H bond angle is methane is …………….
Answer:
109°28′

34. The existence of huge number of carbon compounds are due to two properties of carbon : tetravalency and ……………
Answer: catenation

35. n-propyl alcohol and iso-propyl alcohol exhibit…………… isomerism.
Answer:
positional

36. Methane, ethane and propane are the first three members of a ………….. series.
Answer:
homologous

37. …………. is the main constituent of CNG.
Answer:
Methane

38. Ethanoic acid is commonly known as…………..acid.
Answer:
acetic

39. IUPAC name of formic acid is …………
Answer:
methanoic acid

State whether the following statement is True or False : VSA

1. One must not drive a car after consuming alcohol._________________
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

2. Denatured spirit cannot be consumed orally._____________________
Answer:
True

3. ‘Carbon’ comes from the Latin word ‘carbo’ meaning coal.
Answer:
True

4. Methane is the main constituent of marsh gas.
Answer:
True

5. Industrially ethane is produced by catalytic cracking of petroleum.
Answer:
True

6. Burning of methane in air is an exothermic reaction.
Answer:
True

7. PVC is highly fire resistant,
Answer:
True

8. Ethanol is used as a solvent in laboratory.
Answer:
True

9. Ethanol damages the optic nerve and may cause blindness.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 8.6 Organic Chemistry

10. Teflon is hydrophobic and high heat resistant.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity can serve as a valuable review tool before exams.

Current Electricity Class 10 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1.
The SI unit of electric charge is:
(A) Coulomb
(B) Ampere
(C) Ohm
Answer:
((A) Coulomb

Question 2.
The unit of potential difference is :
(A) joule
(B) volt
(C) ohm
(E) ampere
Answer:
(B) volt

Question 3.
The unit of electrical power is:
(A) volt
(B) watt
(C) ohm
(D) joule
Answer:
(B) wait

Question 4.
What material an electric fuse made of?
(A) copper
(B) silver
(C) iron
(D) tin-lead alloy
Answer:
(D) Tintead alloy

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 5.
Unit of resistance is:
(A) ampere
(B) ohm
(C) coulomb
(D) joule
Answer:
(B) ohm

Question 6.
Specific resistance of a conductor dipends on :
(A) its length
(B) its cross-sectional area
(C) its material
Answer:
(C) its nateriat

Question 7.
The amount of heat developed due to current can be known from:
(A) Ampere’s law
(B) Ohm’s law
(C) Joules law
Answer:
(C) Joules lau

Question 8.
The example of conservation of electrical energy into mechanical energy is:
(A) electric cell
(B) electric motor
(C) electric lamp
Answer:
(B) electric motor

Question 9.
The action of electric current on magnet was first observed by:
(A) Oerested
(B) Joule
(C) Barlow
(D) Newton
Answer:
(A) Oerested

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 10.
Ohm’s law is related to:
(A) current and potential difference
(B) volume and pressure
(C) temperature density.
Answer:
(A) current and potenitial difference

Question 11.
Electric supply company measures the electricity consumed by the consumers in their household in terms of :
(A) joule unit
(B) watt-hour
(C) B.O.T. units
Answer:
(C) B.OT inits

Question 12.
Which one is not conductor of electricity:
(A) copper
(B) gold
(C) aluminium
(D) plastic
Answer:
(D) plastic

Question 13.
Ammeter measures:
(A) resistance
(B) potential difference
(C) current
Answer:
(C) current

Question 14.
Potential difference is measured by:
(A) Voltmeter
(B) Volameter
(C) Galvanometer
Answer:
(A) Voltmeter

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 15.
If the length of the conductor is kept unaltered and cross section of conductor is increased then its resistance:
(A) increases
(B) decreases
(C) remains unaltered
Answer:
(B) decreases

Question 16.
If the corss section of the conductor is kept unaltered and length of conductor is increased then its resistance:
(A) increases
(B) decreases
(C) remains unaltered
Answer:
(A) increases

Question 17.
The correct relation is :
(A) Watt = \(\frac{\text { Volt }}{\text { Ampere }}\)
(B) Watt = \(\frac{\text { Ampere }}{\text { Volt }}\)
(C) Watt = Volt × Ampere
Answer:
(C) Watt = Volt × Ampere

Question 18.
The physical quantity measured by kilowatt-hour
(A) Electric power
(B) Electric energy
(C) Current
Answer:
(B) Electric energy

Question 19.
What is the equivalent resistance of the resistances 2 ohm, 3 ohm and 5 ohm combined in parallel ?
(A) 10 ohm
(B) \(\frac{30}{31}\) ohm
(C) \(\frac{31}{30}\) ohm
(D) 20 ohm
Answer:
(B) \(\frac{30}{31}\) ohm

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 20.
What is the equivalnnt resistance of the resistances 3 ohm, 5 ohm and 12 ohm combined in series?
(A) 15 ohm
(B) 18 ohm
(C) 20 ohm
(D) 30 ohm
Answer:
(C) 20 ohm

Question 21.
Force between two charges separated by a certain distance in air is F. If each charge was doubled and distance between them also doubled, then force would be
(A) F
(B) 2 F
(C) 4 F
(D) F / 4
Answer:
(A) F

Question 22.
What is the dimensional formula of electric charge ?
(A) [M0 L0 TA]
(B) [M0 L0 T-1 A]
(C) [M0 L0 TA-1]
(D) [M0 L0 T-1 A-1]
Answer:
(A) [M0 L0 TA]

Question 23.
A charge q1 exerts some force on a second charge q2. If a hird charge q3 be brought near, the force of q1 exerted on q2.
(A) decreases
(B) increases
(C) remains unchanged
(D) increases if q3 is of same sign as q}1 and decreases of q3 is of opposite sign.
Answer:
The force between q1 and q2 is not affected by q3.

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 24.
The dimensional formula of electric density is
(A) MLT-2 A-1
(B) MLT-3 A-1
(C) ML2 T-3 A-1
(D) ML2 T-3 A-2
Answer:
(A) MLT-3 A-1

Question 25.
Electric flux at a point in an electric field is:
(A) positive
(B) negative
(C) zero
(D) none of these
Answer:
(C) zero

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 26.
A soap bubble is charged to a potential of 16 V. Its radius is the doubled. The potential of the bubble now will be :
(A) 16 V
(B) 8 V
(C) 4 V
(D) 2 V
Answer:
(B) 8 V

Question 27.
A resistor of 0.5 Ω is connected to another resistor is parallel combination to get an equivalent resistance of 0.1 Ω. The resistance of second resistor is :
(A) 1/8 Ω
(B) 0.2 Ω
(C) 0.6 Ω
(D) 8 Ω
Answer:
(A) 1/8Ω

Question 28.
If six identical cells are each having emf of 6 V are connected in parallel the emf of the combination is :
(A) 1 V
(B) 1 / 6V
(C) 6 V
(D) 36 V
Answer:
(C) 6 V

Question 29.
The resistance of discharge tube is :
(A) ohmic
(B) non-ohmic
(C) both
(D) sometimes ohmic, sometimes non-ohmic.
Answer:
(B) non-ohmic.

Question 30.
A wire of resistance 1 W is stretched to double its length. The resistance will become
(A) 1/4
(B) 1
(C) 2
(D) 4
Answer:
(D) 4

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 31.
A car battery has emf 12 V and internal resistance 5 × 10-2 W. If it draws 60 A current, the terminal voltage of the battery will be
(A) 3 V
(B) 5 V
(C) 9 V
(D) 15 V
Answer:
(C) 9 V

Question 32.
The specific resistance of a wire depends upon :
(A) length
(B) cross sectional area
(C) mass
(D) none of these
Answer:
(D) None of these.

Question 33.
What is the unit for specific resistivity?
(A) Ohm-cm-2
(B) Ohm-cm1
(C) Ohm-cm
(D) Ohm-cm-2
Answer:
(C) Ohm-cm

Question 34.
A battery having emf 4 V and internal resistance 0.5 W is connected with a resistance of 4.5 W, then the voltage at the terminals of battery is :
(A) 4.5 V
(B) 3.6 V
(C) 0 V
(D) 2 V
Answer:
(B) 3.6 V

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 35.
The unit of specific conductivity is:
(A) ohm-cm-1
(B) ohm-cm-2
(C) ohm-1-cm-1
(D) ohm-1 cm-2
Answer:
(C) ohm-1 cm-1

Question 36.
The length of a wire is doubled. Its conductance will be :
(A) unchanged
(B) halved
(C) doubled
(D) quadrupled
Answer:
(B) halved.

Question 37.
Practical unit of resistance is ohm is equal to :
(A) 109 emu
(B) 107 emu
(C) 1011 emu
(D) 1013 emu
Answer:
(A) 109 emu

Question 38.
How many electrons constitute current of IA?
(A) 6.25 × 109
(B) 6.25 × 1018
(C) 6.25 × 105
(D) 6.25 × 106
Answer:
(B) 6.25 × 1018

Question 39.
The resistance will be least in a wire with dimension
(A) L/2,2 A
(B) 2L, A
(C) L, A
(D) none of these
Answer:
(A) L/2,2A.

Question 40.
A cell of negligible resistance and emf 2V is connected to series combination of 2,3 and 5 ohm. The potential difference in vol across the 3 W resistance will be
(A) 6 V
(B) 3 V
(C) 2 / 3 V
(D) 0.6 V
Answer:
0.6 V

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 41.
The material of a wire of a potentiometer is :
(A) copper
(B) steel
(C) manganin
(D) aluminium
Answer:
(C) magnanin.

Question 42.
Kirchhoff’s current law obeys conservation of :
(A) charge
(B) momentum
(C) energy
(D) none of these
Answer:
(A) charge.

Question 43.
Potentlometer measures potential more accurately because :
(A) It uses sensitive galvanometer for null deflection.
(B) It uses high resistance potentiometer wire.
(C) It measures the potential in the closed circuit.
(D) It measures the potential in the open circuit.
Answer:
(A) It uses sensitive galvanometer for null deflection.

Question 44.
A current loop placed in a magnetic field behaves like a:
(A) Magnetic dipole
(B) Magneitc substance
(C) Magnetic pole
(D) All are true
Answer:
(A) Magnetic dipole.

Question 45.
A charge + q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charged will be towards
(A) North
(B) South
(C) West
(D) East
Answer:
(C) West.

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 46.
The vertical component of earth’s magnetic field is zero at a place where angle of dip is :
(A) 0°
(B) 45°
(C) 60°
(D) 90°
Answer:
(A) 0°

Question 47.
A magnetic needle suspended freely orients itself :
(A) in a definite direction
(B) in no direction
(C) upward
(D) downward
Answer:
(A) in a definite direction.

Question 48.
A material when placed in a magnetic field is thrown out of it. Then the material is :
(A) paramagnetic
(B) diamagnetic
(C) ferromagnetic
(D) non-magnetic.
Answer:
(B) diamagnetic.

Question 49.
Which of the following is an Ohmic resistance?
(A) diode value
(B) junction diode
(C) carbon-arc lamp
(D) nichrome
Answer:
(D) nichrome

Question 50.
For which of the following substances, resistance decreases with increase in temperature?
(A) copper
(B) mercury
(C) carbon
(D) platinum
Answer:
(C) carbon

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 51.
In parallel combination of resistances –
(A) p.d. is same across each resistance
(B) total resistance is increased
(C) current is same in each resistance
(D) all of these are true
Answer:
(A) p.d. is same across each resistance

Question 52.
The main fuse is connected in :
(A) live wire
(B) neutral wire
C) both the live and earth wires
(D) both earth and neutral wire
Answer:
(A) live wire

Question 53.
The electric meter in a house records :
(A) charge
(B) current
(C) energy
(D) power
Answer:
(C) energy

Question 54.
When two negative charges are placed close together then :
(A) they attract each other
(B) they repel each other
(C) they become positive
(D) none of the above
Answer:
(B) they repel each other

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 55.
If a source of EMF is traversed from negative to positive terminal, the potential change is :
(A) negative
(B) positive
(C) zero
(D) both negative\positive
Answer:
(B) positive

Question 56.
When the distance between the two charges are halved, the electrical force between the charges
(A) doubles
(B) reduces to one fourth
(C) halves
(D) quadraples
Answer:
(D) quadraples

Question 57.
Mercury behaves as a superconductor
(A) below 4.2K
(B) above 6.9 K
(C) below 23 K
(D) above 9.6 K
Answer:
(A) below 4-2 K

Question 58.
When a cell is in use, its emf E and terminal voltage v are related as :
(A) E = V
(B) E < V
(C) E > V
(D) none of these
Answer:
(C) E > V

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 59.
Which one of the following behaves as a superconductor?
(A) platinum above 273 K
(B) mercury below 4.2K
(C) gold below -191°C
(D) fullerene at room temperature
Answer:
(B) mercury below 4.2K

Question 60.
If one of the resistors in a parallel circuit is removed, the total resistance will be :
(A) double
(B) same
(C) increased
(D) constant
Answer:
(C) increased

Question 61.
The flow of current in a circuit due to short circuit :
(A) reduces
(C) increases rapidly to dangerous level
(B) remains unchanged
(D) increases gradually
Answer:
(C) increases rapidly to dangerous level

Question 62.
If unit of I is ampere, unit of R is ohm, unit of t is second, then unit of H} is :
(A) Joule
(B) watt
(C) dyne / cm2
(D) ohm-1
Answer:
(A) Joule

Question 63.
The relation between H, I, R and t is :
(A) H = I2 R/t
(B) H/t = I2R
(C) R = I2 t/H
(D) I2 = HR/t
Answer:
(B) H/t = l2 R

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 64.
The filament of an incandescent bulb is ma e up of :
(A) tungsten
(B) aluminium
(C) copper
(D) nichrome
Answer:
(A) tungsten

Question 65.
Which of the following properties is not suitable for a fuse wire?
(A) low melting point
(B) high resistance
(C) thick and short in length
(D) thin and short in length
Answer:
(C) thick and short in length

Question 66.
The commercial unit of electrical energy we use is :
(A) wh
(B) kwh
(C) kw
(D) kilowatt.second
Answer:
(B) kwh

Question 67.
If an electrical appliance has E E R = 3.1, it is rated as :
(A) 2 star
(B) 3 star
(C) 4 star
(D) 5 star
Answer:
(D) 5 star

Question 68.
The electric meter in a house records
(A) energy
(B) current
(C) power
(D) charge
Answer:
(A) energy

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 69.
Which one among the following is most energy efficient ?
(A) CFL
(B) tube light
(C) LED
(D) Incandescent lamp
Answer:
(C) LED

Question 70.
In a parallel circuit of bulbs
(A) same current exists in all the bulbs
(B) voltage across each bulb remains the same
(C) failure of any bulb leads to a break in the circuit
(D) All the above
Answer:
(B) voltage across each bulb remains the same

Question 71.
A current carrying conductor produces
(A) electric field
(B) magnetic field
(C) both
(D) none of these
Answer:
(B) magnetic field

Question 72.
A split ring in motion is called :
(A) armature
(B) rotor
(C) core
(D) commutator
Answer:
(d) commutator

Question 73.
The direction of an induced current can be predicted by :
(A) Ampere’s swimming rule
(B) Fleming’s left hand rule
(C) Fleming’s right hand rule
(D) Right-hand thumb rule
Answer:
(C) Fleming’s right hand rule

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 74.
The frequency of alternating current supplied in India is :
(A) OHz
(B) 50 Hz
(C) 110 Hz
(D) 220 Hz
Answer:
(B) 50 Hz

Question 75.
Lenz’s law supports the principle of conservation of :
(A) mass
(B) energy
(C) momentum
(D) charge
Answer:
(B) energy

Question 76.
In commercial alternators, the rotor consists of
(A) armature coil
(B) brushes
(C) field magnets
(D) none of these
Answer:
(C) field magnets

Question 77.
The commercial generation frequency in India is :
(A) 50 Hz
(B) 60 Hz
(C) 100 Hz
(D) 150 Hz
Answer:
(A) 50 Hz

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

Question 78.
DC generators are also called :
(A) dynamo
(B) inverter
(C) storage cell
(D) alternator
Answer:
(D) alternator

Question 79.
The potential difference between the live wire and the neutral wire in domestic circuit is :
(A) 220 V
(B) 11 KV
(C) 33 KV
(D) 132 KV
Answer:
(A) 220 V

Question 80.
A switch must be connected in
(A) neutral wire
(B) live wire
(C) earth wire
(D) either live wire or neutral wire
Answer:
(B) live wire

Question 81.
Which of the two wires of a household ctrcuit are at the same potential?
(A) Live and Neutral
(B) Live & Earth
(C) Neutral and Earth
(D) None of them
Answer:
(C) Neutral and Earth

Fill in the blanks :

1. Coulomb = _____ × second.
Answer:
ampere

2. The equivalent resistance is smaller than the resistance in a parallel combination of _____ resistances.
Answer:
smallest

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

3. Potential difference = current × ______.
Answer:
resistance

4. 12 rt is some electrical _____.
Answer:
work

5. Power = potential difference × ______.
Answer:
current

6. Resistance of a wire is _____ proportional to the length of the wire.
Answer:
directly

7. A _____ is used to measure the potential difference between two points in a section of an electrical circuit.
Answer:
voltmeter

8. An ammeter is used to measure the _____ flowing through an electric circuit where the ammeter is connected in series.
Answer:
current

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

9. Short circuit occurs due to accidental direct contact of the live and the _____ wires.
Answer:
neutral

10. The total resistance of a number of resistors in series is equal to the ______ of the resistances of the component resistors.
Answer:
sum

11. Elecctomotive force is some _____ not a force.
Answer:
energy

12. In current electricity, the potential difference between two points is measured by the work done when unit _____ flows from one point to the other.
Answer:
charge

13. Potential difference between two points one _____ when work done to carry one coulomb charge between the points be 1 Joule.
Answer:
volt.

14. Resistance is the natural property of every material body by virtue of which the body _____ flow of electric charges through it.
Answer:
opposes

15. The current flowing through a conductor is directly proportional to the potential difference between its ends when _____ and other physical conditions of the conductor remain unaltered.
Answer:
temperature

16. Ohm’s law is not valid for current flowing through _____ under low pressure, electrolytes and semi-conductors.
Answer:
gases

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

17. If an electrical instrument of power 1 watt works for 1 hour, the electrical energy expended is known as 1 _____.
Answer:
watt-hour

18. Number of B.O.T. unit = \(\frac{\text { amphere } \times \text { volt }}{1000}\) × _____.
Answer:
hour

19. When electric current does not change the direction it is called _____.
Answer:
Direct Current.

20. Watt = Volt × _______.
Answer:
Ampere

21. The electro magnets are made using the _____ effect of electric current.
Answer:
magnetic

22. Usually the resistance of a conductor _____ with the rise in temperature.
Answer:
increases

23. The SI unit of current is _____.
Answer:
ampere.

24. In Ohm’s law, the _____ and other physical conditions are remaining constant.
Answer:
temperature

25. The temperature remaining constant, the resistance between two opposite forces of a unit cube of a conductor is called its _____.
Answer:
specific resistance.

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

26. The watt-hour is the practical unit of _____ energy.
Answer:
electrical.

27. Like charges _____ each other.
Answer:
repel

28. SI unit of electric potential is _____.
Answer:
volt.

29. Electric fuse is a _____, device.
Answer:
safety

30. Fleming’s left hand rule is also called _____ rule.
Answer:
motor.

31. An electric generator converts _____ energy into electrical energy.
Answer:
mechanical.

32. The other name of potential difference is _____.
Answer:
voltage

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

33. The amount of energy given to each coulomb of charge passing through a 12 V battery is _____ J.
Answer:
12

34. The unit of \varepsilon_0 (permitivity in vacuum) is _____.
Answer:
C2 N-1 m-2

35. Resistivity of silver _____ with increase in temperature.
Answer:
increases

36. An ideal cell should have _____ internal resistance.
Answer:
zero

37. Mica is an _____.
Answer:
insulator

38. _____ filament is used in incandescent bulb.
Answer:
tungsten

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

39. Tube-lights are _____ power efficient than incandescent bulbs.
Answer:
more

40. CFLs and LED bulbs are _____ efficient than filament-type bulb.
Answer:
more

41. More the number of stars in an electrical appliance, _____ is its efficiency.
Answer:
higher

42. SI unit of magnetic field strength is _____.
Answer:
Tesla

43. The magnetic effect of current was discovered by _____.
Answer:
Oersted

44. The direction of induced current can be predicted by _____ law.
Answer:
Lenz’s

45. Laws of electromagnetic induction was proposed by _____.
Answer:
Faraday

46. In our houses, we have electric supply of frequency _____ Hz.
Answer:
50

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

47. In an alternator, the stator consists of the _____.
Answer:
armature.

48. The house wiring is done in a ______ system.
Answer:
tree

49. The earth wire should be connected to the _____ of the appliance.
Answer:
body

State whether the following statement is True or False : VSA

1. An ammeter is connected in series in a circuit and a voltmeter is connected in parallel.
Answer:
True

2. Electric current is the flow of charge.
Answer:
True

3. Electric current is vector quantity.
Answer:
False

4. All types of conductors obey ohma’s law
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

5. Below 4.2K, mercury behaves as a superconductor.
Answer:
True

6. Resistance of materials in superconducting state is infinity high.
Answer:
False

7. If current flowing through a wire is doubled, the heat produced will also be doubled.
Answer:
False

8. An incandescent bulb is an energy efficient bulb.
Answer:
False

9. Watt is a much smaller unit of electrical power.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

10. We should buy electrical appliance with lower star-rating.
Answer:
False

11. Barlow’s wheel works on alternating current.
Answer:
False

12. At the centre of the circular loop, the magnetic field line is straight.
Answer:
True

13. Lenz’s law is in accordance with the law of conservaion of energy.
Answer:
True

14. A direct current can be stepped up for transmission.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 6 Current Electricity

15. The earth is considered to be at zero potential.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light can serve as a valuable review tool before exams.

Light Class 10 WBBSE MCQ Questions

Multiple Choice Questions (MCQ) :

Question 1
The formation of spectrum is due to:
(A) reflection
(B) refraction
(C) dispersion of light
Answer:
(C) dispersion

Question 2.
The terminal colours of pure spectrum of white light are:
(A) Blue and violet
(B) Red and orange
(C) Red and violet
Answer:
(C) Red and violet

Question 3.
Yellow colour is called:
(A) primary
(B) secondary
(C) middle colour.
Answer:
(B) secondary colour

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 4.
The (A) seven (B) six (C) eight colours can be seen distinctly in pure spectrum.
Answer:
(A) seven

Question 5.
The dispersion of white light was first observed by :
(A) Sir Issac Newton
(B) Boyle
(C) Max well
Answer:
(A) Sir Issac Newton

Question 6.
The would be towards the base of the prism.
(A) violet
(B) green
(C) orange
Answer:
(A) violet

Question 7.
The arrangement of seven colours of spectrum is:
(A) VIBGYOR
(B) VBIGOYR
(C) RAINBOW
Answer:
(A) VIBGYOR

Question 8.
Linear magnification is equal to:
A (length of image) / (length of the object)
(B) (length of image) × (length of the object)
C) (length of image) + (length of the object)
(D) (length of image) – (length of the object)
Answer:
(B) (length of image) × (length of the object)

Question 9.
The object is placed in between ‘f’ and ‘2f’ in convex lens, the size of image will be
(A) greater in size the object
(B) smaller in size than the object
(C) equal in size of the object.
Answer:
(A) greater in size than the object.

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 10.
To form virtual image on the same side of the object in case of convex lens, object should be placed:
(A) in between the lens and the focus
(B) in between ‘f’ and ‘2f’
C) at ‘2f’ from the lens
(D) at a distance greater than ‘2f’ from the lens.
Answer:
(A) in beiveen the lens and the focus

Question 11.
To form the image of real, inverted and equal to the size of the object, the object should be placed:
(A) in between the lens and the focus
(B) at a distnace greater then ‘2f’ from the lens
(C) at ‘2f’ from the lens
(D) in between ‘f’ and ‘2f’
Answer:
(C) at ‘2f’ from the lens

Question 12.
A plane mirror produces a magnification of :
(A) -1
(B) +1
(C) Zero
(D) between O and + α
Answer:
(B) +1

Question 13.
When a mirror is rotated through an angle θ, the reflected ray from it turns through an angle of
(A) θ
(B) \(\frac{\theta}{2}\)
(C) 2 θ
(D) 0
Answer:
(C) 2 θ

Question 14.
An object is placed at a distance of 40 cm in front of a concave mirror of focal length 20 cm. The image produced is
(A) virtual and inverted
(B) real and erect
C) real, inverted and diminished
(D) real, inverted and of some size as the object.
Answer:
(D) real, inverted and of same size as the object.

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 15.
A plane mirror is approaching a person at a speed of 5 cm s-1. At what speed will his image approach him ?
(A) 10 cm s-1
(B) 5 cm s-1
(C) 20 cms-1
(D) 15 cm s-1
Answer:
(A) 10 cms-1

Question 16.
An object is placed between two plane mirrors inclined at an angle of 30°, then total number of images formed is
(A) 12
(B) 2
(C) 11
(D) infinite
Answer:
(C) 11

Question 17.
A ray is incident at an angle 38° with a mirror. The angle between normal and reflected ray is
(A) 38°
(B) 52°
(C) 90°
(D) 76°
Answer:
(B) 52°

Question 18.
A concave mirror gives an image three times as large as the object placed at a distance of 420 cm from it. For the image to be real, the focal length should be
(A) 10 cm
(B) 15 cm
(C) 20 cm
(D) 30 cm
Answer:
(B) 15 cm

Question 19.
A concave mirror of focal length f (in air) is immersed in water (μ=\(\frac{4}{3}\)). The focal length of the mirror in water will be
(A) f
(B) [altex]\frac{4}{3}[/latrex] f
(C) \(\frac{3{4}\) f
(D) \([\frac{7{3}\) f
Answer:
(A) f

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 20.
A mirror produces magnified erect image of an object. The nature of mirror is
(A) convex
(B) concave
(C) neither convex nor concave
(D) plane
Answer:
(B) concave

Question 21.
A ray of light is incident normally on a plane mirror. The angle of reflection will be
(A) 135°
(B) 90°
(C) 45°
(D) 0°
Answer:
(D) 0°

Question 22.
The focal length f of a spherical mirror of radius of curvature R is
(A) \(\frac{R}{2}\)
(B) R
(C) \(\frac{3}{2}\) R
(D) 2 R
Answer:
(A) \(\frac{R}{2}\)

Question 23.
In which of the following cases, man will not see image greater than himself ?
(A) Concave mirror
(B) Convex mirror
(C) Plane and Concave
(D) None of these.
Answer:
(B) Convex mirror

Question 24.
If an object is 30 cm away from a cancave mirror of focal length 15 cm, the image will be
(A) erect
(B) virtual
(C) diminished
(D) of same size
Ans:
(D) of same size

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 25.
The number of images observable between two parallel plane mirrors is
(A) 2
(B) 4
(C) 11
(D) infinite
Ans:
(D) infinite

Question 26.
The focal length of a canvex lens is 30 cm and the size of image is a quarter of the object, then the object distance is
(A) 90 cm
(B) 60 cm
(C) 30 cm
(D) 40 cm
Ans:
(A) 90 cm

Question 27.
Focal length of a convex lens will be maximum for
(A) blue light
(B) yellow light
(C) green light
(D) red light.
Answer:
(D) red light

Question 28.
A lens is behaving as convex lens in air and concave in water then its refractive index is
(A) smaller than air
(B) greater than both air and water
(C) greater than air, but less than water
(D) almost equal to water.
Answer:
(C) greater than air, but less than water

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 29.
The plane surface of a plano-convex lens of focal length f is silvered. It will behave as
(A) plane mirror
(B) convex mirror of focal length 2f
(C) concave mirror of focal length f/2
(D) None of the above
Answer:
(C) concave mirror of focal length f2

Question 30.
Mirage is a phenomenon due to
(A) reflection of light
(B) refraction of light
(C) total internal reflection of light
(D) diffraction of light.
Answer:
(C) total internal reflection of light.

Question 31.
The principle behind optical fibres is
(A) total internal reflection
(B) total external reflection
(C) both (A) and (B)
(D) diffraction.
Answer:
(A) total internal reflection.

Question 32.
A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will
(A) become zero
(B) become infinite
(C) reduce
(D) increase
Answer:
(B) become infinite

Question 33.
A convex lens will become less convergent in
(A) oil
(B) water
(C) both
(D) none
Answer:
(B) water

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 34.
Which of the following colours suffers maximum deviation in a prism?
(A) yellow
(B) blue
(C) green
(D) orange
Answer:
(B) blue

Question 35.
The splitting of white light into several colours on passing through a glass prism is due to
(A) refraction
(B) reflection
(C) interference
(D) diffraction
Answer:
(A) refraction

Question 36.
Rainbow is formed due to a combination of
(A) refraction and absorption
(B) dispersion and focussing
(C) refraction and scattering
(D) dispersion and total internal reflection
Answer:
(D) dispersion and tota’ internal reflection

Question 37.
Which of the prism is used to see infrared spectrum of light ?
(A) rock salt
(B) nicol
(C) flint
(D) crown
Answer:
(A) rock salt

Question 38.
Myopia is due to
(A) older age
(B) shortening of eye ball
(C) irregular change in focal length
(D) elongation of eye ball.
Answer:
(D) elongation of eve ball

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 39.
A person cannot see objects clearly beyond 2 m. The power of lens required to correct his vision will be
(A) +2 D
(B) -1 D
(C) +1 D
(D) -0.5 D
Answer:
(D) -0.5 D

Question 40.
A person uses spectacle of power +2D. He is suffering from
(A) short sightedness of myopia
(B) long sightedness of hypermetropia
(C) presbyopia
(D) astigmatism
Answer:
(B) long sighteciness of hypermetropia

Question 41.
Which of the following materials cannot be used to make a lens ?
(A) water
(B) glass
(C) clay
(D) plastic
Answer:
(C) clay

Question 42.
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be :
(A) plane only
(B) concave only
(C) convex only
(D) eighter plane or convex
Answer:
(D) eighter plane or convex

Question 43.
A ray of light suffers refraction through an equilateral prism. The deviation produced by the prism does not depend on the :
(A) angle of incidence
(B) colour of light
(C) size of the prism
(D) material of the prism
Answer:
(C) stze of the prism

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 44.
A ray of light incident on a lens parrallel to its principal axis, after refraction passes through or appears to come from :
(A) its second focus
(B) its first focus
(C) its optical centre
(D) the centre of curvature of its second surface
Answer:
(A) its second fucus

Question 45.
The source of ultra-violet light is :
(A) electric bulb
(B) carbon arc lamp
(C) red hot iron bulb
(D) sodium vapour lamp
Answer:
(B) carbon arc lamp.

Question 46.
A mirror having a very wide fleld of view must be
(A) concave
(B) convex
(C) plane
(D) none of these
Answer:
(B) convex

Question 47.
Linear magnification (m) of a convex mirror is :
(A) greater than one
(B) less than one
(C) zero
(D) equal to one
Answer:
(B) less than one

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 48.
Back side of a shining stainless steel spoon resembles :
(A) a concave mirror
(B) a convex mirror
(C) a plane mirror
(D) a prism
Answer:
(B) a convex mirror

Question 49.
Front side of a shining stainless steel spoon resembles
(A) a concave mirror
(B) a convex mirror
(C) a plane mirror
(D) a prism
Answer:
(A) concave mirror

Question 50.
If a concave mirror having focal length f is immersed in water (\mu=\frac{4{3), then the new focal length would be :
(A) \(\frac{4}{3}\) f
(B) \(\frac{3}{4}\) f
(C) f
(D) \(\frac{7}{4}\) f
Answer:
(C) f

Question 51.
Snell’s law is not valid when the angle of incidence is :
(A) 0°
(B) 45°
(C) 60°
(D) 90°
Answer:
(A) 0°

Question 52.
Refraction is caused by :
(A) different wave speeds
(B) more than one reflection
(C) displaced images
(D) bending
Answer:
(A) different wave speeds

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 53.
A swimming pool appears to be 2 m deep. It’s actual depth is (\mu for water = 1.33)
(A) 2.66 m
(B) 2 m
(C) 2.34 m
(D) 2.54 m
Answer:
(A) 2.66 m

Question 54.
Which one of the following can not be used to make a lens?
(A) water
(B) transparent plastic
(C) glass
(D) iron
Answer:
(D) iron

Question 55.
The power of comblnation of two lenses of power +1.5D and -2.5 D is :
(A) -D
(B) 4 D
(C) +4 D
(D) +D
Answer:
(A) -D

Question 56.
The size of the pupil is adjusted by :
(A) cornea
(B) iris
(C) retina
(D) aqueous human
Answer:
(B) iris

Question 57.
The power of a lens is -1.5 D. It’s focal length is :
(A) -1.5 cm
(B) -15 cm
(C) 66.6 cm
(D) -66.6 cm
Answer:
(D) -66.6 cm

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 58.
The colour of light which suffers maximum bending while passing through a glass prism is :
(A) green
(B) red
(C) yellow
(D) violet
Answer:
(D) violet

Question 59.
The three primary colours are :
(A) red, blue, yellow
(B) red, green, yellow
(C) yellow, green, orange
(D) red, green, blue
Answer:
(D) red, green, blue

Question 60.
The colour of an object is the same as the light that is:
(A) transmitted
(B) absorbed
(C) reflected
(D) All of these
Answer:
(C) reflected

Question 61.
Compared to ultraviolet waves, the wave length of infrared waves is:
(A) shorter
(B) longer
(C) the same
(D) faster
Answer:
(B) longer

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

Question 62.
If there were no atmosphere, the cloudless sky would have appeared
(A) blue
(B) violet
(C) red
(D) black
Answer:
(d) black

Fill in the blanks :

1. A convex lens is called a _______ lens.
Answer:
converging

2. The middle colour is _______.
Answer:
yellow

3. Yellow and blue colours are _______ colours of each other.
Answer:
complementary

4. Maggenta colour is made by mixing red and ______ colour.
Answer:
blue

5. Red flower appears ______ in green light.
Answer:
black

6. During dispersion of light, which light is splitting up into ______ colours.
Answer:
seven

7. A __________ lens is used as a magnifying glass.
Answer:
convex

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

8. A beam of rays of light parallel to the principal axis of a convex lens, will passes through the ______ focus after refraction.
Answer:
principal

9. The elementary colours white light are arranged in order of _______.
Answer:
wave length

10. The band of different colours obtained due to dispersion of white light is called the _______.
Answer:
spectrum

11. ______ first observed the dispersion of white light.
Answer:
Sir Issac Newton

12. Starting from the violet and writing the first latter of the seven colours of the spectrum it is called _______.
Answer:
VIBGYOR

13. The lens which is thinner at the centre and wider at the two edges is known as a _______ lens.
Answer:
convex

14. Lenses are generally of two types, concave and ______.
Answer:
convex

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

15. If a ray be incident on a convex lens parallel to its principal axis, then the refracted ray through the lens passes through the ______ of the lens.
Answer:
focus.

16. The straight line joins the centres of the spherical surfaces forming the lens is called the _______ axis of the lens.
Answer:
principal

17. The distance of the principal focus from the optical centre of a lens is called its principal ______ length.
Answer:
focal

18. An object place perpendicular to the principal axis of a convex lens will have its image _______ to the principal axis.
Answer:
Perpendicular

19. A transparent body absorbs all the colours of white light except the light of colour of its _______.
Answer:
own

20. Yellow colour is a _______ colour.
Answer:
secondary.

21. The light which consists of only one colour is called ______ light.
Answer:
monochromatic

22. A convex mirror always produces a ______ Image.
Answer:
virtual

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

23. Refractive index of a medium depends upon ________ of the light.
Answer:
colour.

24. A red flower apprears ______ in green light.
Answer:
black

25. The sky appears blue due to ______ of light.
Answer:
sca tteroing

26. In human eye the image is formed on _______.
Answer:
retina

27. A ________ mirror is used as a shaving mirror.
Answer:
infinity

28. The radius of curvature of a spherical mirror is 20 cm. Its focal length is ______ cm.
Answer:
10

29. ______ In 1841 was the first to give a systematic analysis of formation of images under paraxial approximation.
Answer:
Gauss

30. Only rays inclined at an angle less than about _______ to the principal axis is considered as paraxial rays.
Answer:
10°

31. The radius of curvature of a convex mirror is ______ Its focal length.
Answer:
twice

32. As angle of prism increases, angle of deviation ______.
Answer:
increases

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

33. When for a particular angle of incidence, the angle of deviation is minimum, the position is known as ______ position of the prism.
Answer:
minimum deviation

34. In case of a rectangular glass slab, the emergent ray is _______ to the incident ray.
Answer:
parallel

35. Refractive index of a gas _______ with increase in temperature.
Answer:
decreases

36. Speed of light in water is lesser than that in air. Hence, air is optically ______ medlum.
Answer:
rarer

37. Magnification produced by a concave lens is always _______.
Answer:
positive

38. If a person walking in a dark room enters into a brightly lit corridor, the pupil of the eye ______.
Answer:
contracts

39. ______ is a hole in the middle of iris.
Answer:
Pupil

40. _______ lens is used as eye-lens in Galllean telescope.
Answer:
Concave

41. When the object is stuated at 2 F1 (i.e. at twice the distance of focal length) from a convex lens, the image formed is real and ______.
Answer:
inverted

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

42. When a red’ flower is viewed in green light it appeans _____.
Answer:
black.

43. _____ discovered the dispersion of light by a prism.
Answer:
Newton

44. Among the visible light, _______ coloured light is deviated the least.
Answer:
red

45. ______ are used for studying crystal structure of solids.
Answer:
X-rays

46. ______ rays are used in radio-therapy.
Answer:
Gamma

47. The part of light we can see with our eyes is called _______ spectrum.
Answer:
visible

State whether the following statement is True or False : VSA

1. Concave mirror is used as a rear vlew mirror in cars.
Answer:
False

2. The radius of curvature of a convex mirror is twice its focal length.
Answer:
True

3. The image formed by a convex mirror is inverted and magnified.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

4. Both magnified and diminished image of an object can be formed using a concave mirror.
Answer:
True

5. Speed of light decreases with increase in temperature.
Answer:
False

6. Refractive index of a medium can be less than 1 .
Answer:
False

7. Only the refracting surfaces of a prism need to be transparent.
Answer:
True

8. Myopia is caused due to high converging power of eye-lens.
Answer:
True

9. Cone cells cause the sensation of colour of objects in our eye.
Answer:
True

10. Iris has no colour of its own.
Answer:
False

11. Yellow is referred to as the mean colour.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 5 Light

12. A rectangular glass slab also produces dispersion of light.
Answer:
False

13. A prism itself produces no colours.
Answer:
True

14. Higher the wave length of light, lower will be its frequency.
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Well structured WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena can serve as a valuable review tool before exams.

Thermal Phenomena Class 10 WBBSE MCQ Questions

Multiple choice questions (MCQ) :

Question 1
The Fahrenheit and kelvin scales of temperature will the same reading at
(A) -40
(B) 313
(C) 574.25
(D) 732.25
Answer:
(B) 5 ?

Question 2
At what temperature, volume of an ideal gas at 0°C becomes triple?
(A) 182°C
(B) 819°C
(C) 546°C
(D) 646°C
Answer:
(C) 546°C

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 3.
The specific heat of ice at 0°C melting into at 0°C is:
(A) zero
(B) infinity
C) more than zero
(D) less than zero
Answer:
(B) infinity

Question 4.
Boiling water is changing into steam. The specific heat of boiling water is:
(A) Zero
(B) One
(C) infinity
(D) less than one
Answer:
(C) infinity

Question 5.
Which of the following has the highest specific heat?
(A) copper
(B) water
(C) hydrogen
(D) silver
Answer:
(C) hydrogen

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 6.
One gram of ice at 0°C is added at 5 g of water to 10°C. Final temperature of the mixture is:
(A) -5°C
(B) 5°C
(C) 0°C
(D) none of these
Answer:
(A) -5°C

Question 7.
The specific heat of an ideal gas varies with temperature T as :
(A) T1
(B) T2
(C) T-1
(D) T0
Answer:
(D) T0

Question 8.
22 g CO2 at 27°C is mixed with 16 g of oxygen at 37°C. The temperature of the mixture is :
(A) 32°C
(B) 27°C
(C) 37°C
(D) 30°C
Answer:
(A) 32°C

Question 9.
A ballon contains 500 m3 of He at 27°C and 1 atmospheric pressure. The volume of He at -3°C and 0.5 atmospheric pressure will be:
(A) 700 m3
(B) 900 m3
(C) 1000 m3
(D) 500 m3
Answer:
(B) 900 m3

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 10.
The specific heat of a gas in a gas in an isothermal process is:
(A) infinite
(B) zero
(C) negative
(D) remains constant
Answer:
(A) infinite

Question 11.
100 g of ice is mixed with 100 g of water at 100°C. The final temperature of the mixture is:
(A) 10°C
(B) 20°C
(C) 40°C
(D) 30°C
Answer:
(A) 10°C

Question 12.
Heat given to a body which rises its temperature by 1°C is:
A water equivalent
(B) specific heat
(C) thermal capacity
(D) temperature gradient
Answer:
(C) thermal capacity

Question 13.
During the adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature.
The ratio \(\fracC_p}C_v}\) for gas is :
(A) \(\frac{4}3}\)
(B) 2
(C) \(\frac{5}3}\)
(D) \(\frac{3}2}\)
Answer:
(D)

Question 14.
A gaseous mixture consists of 16 g of Helium and 16 g Oxygen. The ratio \(\fracC_p}C_v}\) of the mixture is :
(A) 1.54
(B) 1.4
(C) 1.63
(D) 1.59
Answer:
(C) 1.63

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 15
Two bars of copper having same length but unequal cross-section are heated to the same temperature. The change in length will be:
(A) equal in both bars
(B) more in thicker bar
(C) more in thinner bar
(D) cannot say
Answer:
(A) equal in both bars

Question 16
A body cools from 60°C to 50°C in 10 min. If room temperature be 25°C, temperature of the body at the end of next 10 min will be:
(A) 38.5°C
(B) 40°C
(C) 45°C
(D) 42.85°C
Answer:
(D) 42.85°C

Question 17
A body takes T minutes is cool from 62°C to 61°C when the surrounding temperature is 30°C. The time taken by the body to cool is 30°C. The time taken by the body to cool 46°C to 45°C is
(A) greater than T minute
(B) equal to T minute
(C) less than T minute
(D) equal to T/2
Answer:
(A) greater than T minute

Question 18
If the temperature of a block body is doubled, the wavelength at which the spectral radiancy has its maximum is :
(A) doubled
(B) halved
(C) quadrupled
(D) unchanged
Answer:
(B) halved

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 19
A black body has maximum wavelength 1 m at 2000 K. Its corresponding wavelength at 3000 K will be :
(A) \(\frac{3}{2}\) λ m
(B) \(\frac{2}{3}\) λ m
(C) \(\frac{16}{81}\) λ m
(D) \(\frac{81}{16}\) λ m
Answer:
(B) \(\frac{2}{3}\) λ m

Question 20.
A body cools from 50°C to 40°C in 5 minutes. Its temperature comes down to 33.33°C in next 5 minutes. The temperature of surrounding is:
(A) 15°C
(B) 20°C
(C) 25°C
(D) 10°C
Answer:
(B) 20°C

Question 21
The rate of cooling at 600 K, if surrounding temperature is 300 K is R. The rate of cooling at 900 K is :
(A) \(\frac{16}{3}\) R
(B) 2 R
(C) 3 R
(D) \(\frac{2}{3}\) R
Answer:
(A) \(\frac{16}{3}\) R

Question 22
If Im denotes the wavelength at which the radiative emission from a black body at a temperature TK is maximum, then
(A) λm ∝ T
(B) λm ∝ T-1
(C) λm ∝ T2
(D) λm does not depend on T.
Answer:
(B) λm ∝ T-1

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 23
Two spheres made of same material have radii in the ratio 1 : 2. Both are at same temperature. Ratio of heat radiation energy emitted per second by them is:
(A) 1 : 2
(B) 1 : 4
(C) 1 : 8
(D) 1 : 16
Answer:
(B) 1 : 4

Question 24.
The coefficient of linear expansion of a solid is :
(A) 3 γ
(B) 2 γ
(C) γ
(D) γ / 3
Answer:
(D) γ / 3

Question 25.
A good insulator of heat is
(A) Copper
(B) Mercury
(C) trapped air
(D) Iron
Answer:
(C) tropped air

Question 26.
A bimetallic strip bends on heating due to :
(A) Uneven expansions
(B) Same expansion
(C) No expansions
(D) None of these
Answer:
(A) Uneven expansions

Question 27.
The coefficient of linear expansion of a solid depends on :
(A) unit of length
(B) scale of temperature
(C) density of the material
(D) None of these
Answer:
(B) scale of temperature

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 28.
A bimetallic strip bends upon heating because of
(A) same expansion
(B) uneven expansion
(C) no expansion
(D) twisting
Answer:
(B) uneven expansion

Question 29.
If the value of coefficient of linear expansion is 1.5 × 10-4 ° C-1 then value of coefficient of superficial expansion is :
(A) 4.5 × 10-4 °C-1
(B) 3.0 × 10-4 ° C-1
(C) 6.0 × 10-4 ° C-1
(D) 7.5 × 10-4 ° C-1
Answer:
(B) 3.0 × 10-4 ° C-1

Question 30.
When a solid metallic sphere is heated, the largest percentage increase occurs in its.
(A) Diameter
(B) Surface area
(C) Volume
(D) Density
Answer:
(C) Volume

Question 31.
For a liquid, the coefficient of apparent expansion (δa) and coefficient of real expansion (γ) are related as :
(A) δa = γr
(B) γa > γru
(C) γa < γr
(D) γa / γr = constant
Answer:
(C) γa < γr

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 32.
Coefficient of linear expansion of the following metals are in the order
(A) aluminium < copper < iron
(B) copper < iron < aluminium
(C) copper < aluminium < iron
(D) aluminium > copper > iron
Answer:
(D) aluminium > copper > iron

Question 33.
The thermal conductivity of a rod is 2. what is its resistivity?
(A) 0.5
(B) 1
(C) 0.25
(D) 2
Answer:
(A) 0.5

Question 34.
Thermal conductivity of which of the following is the maximum?
(A) copper
(B) silver
(C) diamond
(D) platinum
Answer:
(C) diamond

Question 35.
The magnitude of thermal conductivity of the following substances are in the order.
(A) silver > aluminium > glass > wood
(B) aluminium > silver > glass > wood
(C) silver > aluminium > wood > glass
(D) aluminium > silver > wood > glass
Answer:
(A) silver > aluminium > glass > wood

Question 36.
A liquid which is a good conductor of heat is :
(A) kerosin
(B) mercury
(C) water
(D) turpentine
Answer:
(B) mercury

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

Question 37.
For an ideal heat insulator, value of K is :
(A) zero
(B) 1
(C) 100
(D) α
Answer:
(A) zero

Fill in the blanks :

1. Heat is a form of _________.
Answer:
energy.

2. Three different types of motions are translational motion, vibrational motion and ___________.
Answer:
Rotational motion.

3. SI unit of heat is __________.
Answer:
Joule.

4. 1 calorie = __________ Jule.
Answer:
4.18

5. Temperatures are measured with a __________.
Answer:
thermometer.

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

6. ______ is the upper fixed point in Fahrenheit scale.
Answer:
212° F

7. Three types of expansions in solids are, linear expansion, superficial expansion and __________.
Answer:
volume expansion.

8. Real expansion of the liquid = expansion of the vessel + __________.
Answer:
apparent expansion of the liquid.

9. γs = γn + ________.
Answer:
γ8

10. The volume of water is minimum at ______.
Answer:
4°C

11. The density of water is maximum at ______.
Answer:
4°C.

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

12. From Charle’s Law, we find γp = ______ °C-1.
Answer:
\(\frac{1}{273}\)

13. From pressure law, we find γy= ________ °C-1.
Answer:
\(\frac{1}{273}\)

14. Specific heat of water in SI system is ________.
Answer:
4200 Jkg-1 K-1.

15. The unit of thermal conductivity in SI system is ________.
Answer:
Jm-1 s-1 K-1.

16. The unit of thermal conductivity in CGS system is ________.
Answer:
cm2 s-1

17. Carbon dioxide is a ________ gas.
Answer:
green house.

18. The expansion of a substance on heating is called ________ expansion.
Answer:
thermal.

19. The coefficient of linear expansion of a solid does not depend on unit of ________.
Answer:
length.

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

20. Thermal resistivity is the _______ of thermal conductivity.
Answer:
reciprocal.

21. In charles’ law, a _______ mass of gas is taken.
Answer:
given.

22. A liquid good conductor of heat is ________.
Answer:
mercury.

23. In summer the pendulum clock becomes ________.
Answer:
slower

24. The unit of γ (i.e, coefficlent of cubical expansion) in S.I unit is ________.
Answer:
K-1

25. Material of the rod remaining same, longer the rod, ________ will be the increase in length of the rod for same increase in temperature.
Answer:
more.

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

26. If the value of α is 24 × 10-6 °C-1, then its value in S.I. unit is ________.
Answer:
24 × 10-6 K-1

27. Unit of β (coefficient of superficial expansion) is ________.
Answer:
°C-1 or K-1

28. For a particular solid substance, magnitude of β has the value of α [symbols have their usual meaning].
Answer:
twice

29. For two rods of same length and same area of cross-section, if temperature is raised by same amount, iron rod will expand ______ compared to that of the aluminium rod.
Answer:
less

30. The reciprocal of thermal conductivity is known as ________.
Answer:
thermal resistivity.

31. The S.I unit of thermal conductivity is ________.
Answer:
jm-1.k-1.s-1

32. Diamond has ________ value of K (i.e., coefficient of thermal conduction) than copper.
Answer:
higher

33. Brass is a ________ conductor of heat.
Answer:
good

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

34. In solids, heat passes from hotter region to colder region by ________ processes.
Answer:
conduction

State whether the following statement is True or False : VSA

1. In winter the pendulum clock becomes slower.
Answer:
False

2. β (i.e. coefficient of superficial expansion) is the characteristic of the material.
Answer:
True

3. For an ideal gas, (δ i.e., coefficient of cubical expansion) = 1 / 273
Answer:
True

4. α, β and δ are related as follows α : β : δ = 1 : 2 : 3
[Symbols have their usual meaning]
Answer:
True

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

5. Real expansion of the liquid = Apparent expansion of the liquid+volume expansion of the container.
Answer:
True

6. The seasonal changes in a pendulum clock are due to the expansion or contraction of solid substances.
Answer:
True

7. The S.I. unit of thermal conductivity is jm-2 ks-1
Answer:
False

8. Usually metals are good conductors of heat than gases and nonmetals.
Answer:
True

9. Diamond has low value of K (i.e. coefficient of thermal conduction)
Answer:
False

10. In solids, heat passes from hotter region to colder region by convection processes.
Answer:
False

WBBSE Class 10 Physical Science MCQ Questions Chapter 4 Thermal Phenomena

11. A substance with a large thermal conductivity is a good conductor while the one with a small thermal conductivity is a poor heat conductor.
Answer:
True