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

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

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) T^{1}

(B) T^{2}

(C) T^{-1}

(D) T^{0}

Answer:

(D) T^{0}

Question 8.

22 g CO_{2} 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 m^{3} 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 m^{3}

(B) 900 m^{3}

(C) 1000 m^{3}

(D) 500 m^{3}

Answer:

(B) 900 m^{3}

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

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

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 I_{m} denotes the wavelength at which the radiative emission from a black body at a temperature TK is maximum, then

(A) λ_{m} ∝ T

(B) λ_{m} ∝ T^{-1}

(C) λ_{m} ∝ T^{2}

(D) λ_{m} does not depend on T.

Answer:

(B) λ_{m} ∝ T^{-1}

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

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 (δ_{a}) and coefficient of real expansion (γ) are related as :

(A) δ_{a} = γ_{r}

(B) γ_{a }> γ_{r}u

(C) γ_{a }< γ_{r}

(D) γ_{a} / γ_{r} = constant

Answer:

(C) γ_{a} < γ_{r}

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

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.

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. γ_{s} = γ_{n} + ________.

Answer:

γ_{8}

10. The volume of water is minimum at ______.

Answer:

4°C

11. The density of water is maximum at ______.

Answer:

4°C.

12. From Charle’s Law, we find γ_{p} = ______ °C^{-1}.

Answer:

\(\frac{1}{273}\)

13. From pressure law, we find γ_{y}= ________ °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:

cm^{2} 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.

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.

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

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

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

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