# West Bengal Board Class 9 Physical Science Book Solution in English WBBSE

## WBBSE Class 9 Physical Science Question Answer West Bengal Board

### WBBSE Class 9 Physical Science Syllabus West Bengal Board 2023

Chapter 1 Measurement
Measurement and Units: Concept of measurement of physical quantities, units and utility of units, Different Systems [CGS, SI] of Units, Units of different quantities in different systems, all physical quantities do not have units (reason), Fundamental Units and Derived Units, Modem ideas regarding standard length and standard time, Units of Mass (1 kg, 1 g), Unit of volume (1L, 1 m3, 1 mL, 1 cm3, 1 dm3).

Units of quantities having very large and very small magnitude: Sizes of living organisms, from microorganisms to large living species, size of the universe (with the help of the unit of length and unit of time) from subnuclear to galactic objects.

Dimension: Dimensions of physical quantities. Use of exponents in the expression of units.

Measurement: Measuring instruments – the idea of least count, range of the instrument, and error in case of the following instruments only – scale, clocks, measuring cylinder, common balance.

Chapter 2 Forces and Motion
Rest and Motion: Role of the observer in deciding rest and motion. Translation is a change of position and rotation is a change of orientation. Difference between rotation and circular motion.

Equations of Motion: Displacement, speed, velocity, and acceleration. Uniform and non-uniform motion among a straight line. Algebraic and graphical representation (through velocity-time graph only). Representation of displacement and acceleration in velocity-time graph.

• Derivation of the expression s = v.t. from the velocity-time graph.
• v = u + a.t from the velocity-time graph.
• Establishment of the expression s = $$\frac{1}{2}$$.a.t2 and s = u.t + $$\frac{1}{2}$$.a.t2 from the velocity-time graph, when the particle is moving with a uniform acceleration.
• Establishing the equation v2 = u2 + 2as from velocity-time graph.

Newton’s 1st Law of Motion: Force as the cause, and acceleration (change of motion) as an effect: (a) Effective force and balanced force. Addition of forces-Parallelogram law, examples from daily life. Resolution of forces, components examples, (b) Inertia of rest and inertia of motion.

Newton’s 2nd Law of Motion: Newton’s 2nd Law of Motion. Force is the cause, acceleration is an effect, and F = ma is the postulate (law). Mass is the intrinsic property of an object, determining internal resistance (using F = ma). Units of force (Dyne and Newton).

Newton’s 3rd Law of Motion: Newton’s 3rd Law of Motion. Action (force) and reaction (force).

Different types of forces: Forces of different types with examples. Tension is the force between different parts of a string or wire. The idea of normal reaction force.

Linear momentum: Introducing the concept of momentum for an object with variable mass. Necessity of linear momentum as a physical quantity. Statement of Newton’s 2nd law of motion by using the concept of linear momentum. Obtaining F = ma, from this statement when m is constant.

Conservation of linear momentum: Idea of conservation of linear momentum.

Chapter 3 Matter: Structure and Properties
The pressure of liquid and air: Fluid Pressure: Thrust, force per unit area, pressure of a liquid at a point, some characteristics of liquid pressure. Description of Barometer. Measurement of atmospheric pressure by Barometer and forecast of weather. Siphon and its applications; Archimedes’ Principle: Archimedes’ Principle. Buoyancy, floatation, and apparent weight. Density and Relative density; Surface tension: Idea of surface tension from examples of daily life. Factors affecting surface tension of a liquid; Viscosity: Viscosity is the friction of a liquid. Laminar or streamlined and turbulent flow. Density and viscosity are two different quantities. Terminal velocity of an object in a viscous medium. Rate of flow of liquid; Bernoulli’s Theorem: Bernoulli’s Theorem; Elasticity: Elasticity, factors on which elasticity depends, Stress, Strain, Hooke’s law, Elastic constants (Young’s modulus only), and Elasticity in daily life. Ductility; Brittleness; Malleability.

Chapter 4 Matter: Atomic Structure; Physical and Chemical Properties of Matter

Chapter 4.1 Atomic Structure:
Discovery of the electron; Rutherford’s alpha particle experiment; Rutherford’s model of an atom; Limitations of Rutherford’s model; Discovery of Neutron; Electron, proton, and neutron; Qualitative presentation of Bohr-Rutherford model of an atom. Electronic orbits (K, L, M, N, shells); Isotope, isobar, and isotone; Nuclear force; Electronic configuration upto Z = 20; Absorption/emission of energy during electronic transitions between orbits.

Chapter 4.2 Mole Concept:
Mole as a unit of number. Avogadro’s number (NA) and its importance in chemistry, biology, and physics; Concept of gram atom and gram molecule; Atomic mass unit; Molar volume of gases at NTP; Use of molar mass, molar volume, and formula mass in chemical calculations.

Chapter 4.3 Solution:
True solution, colloidal solution, and coarse suspension; Diameter of particles in true and colloidal solutions and coarse suspension; Dissolution of small ions/molecules and macromolecules (protein, DNA, starch) in water; Different colloidal solutions (solid-in-liquid, solid-in-gas, liquid-in-gas, liquid-in-liquid). Emulsions and emulsifiers; Solubility of solids and gases in liquids; Saturated, unsaturated, supersaturated solutions; Crystallization; Concentration of solution and its units; Motion of particles in solution; Non-aqueous solvent.

Chapter 4.4 Acids, Bases, and Salts:
Arrhenius definition of acids and bases; Indicators; Industrial uses of NaOH, H2SO4, HCl, HNO3; Chemical properties of acids (H2SO4, HCl, HNO3; Chemical properties of alkali (NaOH); Safe handling of acids and bases; Importance of aqueous medium in respect of acid-base property; Qualitative introduction to pH; Effect of pH on tooth decay; importance of pH in agriculture and pisiculture; Acidic, basic and amphoteric oxides; Acidification of water due to dissolution of gaseous oxides (CO2, SO2, NO2), Neutralization, Antacids, Normal, acidic and basic salts.

Chapter 4.5 Separation of Components of Mixtures:
Distillation and Fractional distillation; Use of Separatory funnel.

Chapter 4.6 Water:
Physical properties of water that influenced proliferation and maintenance of life; Quality parameters of drinking water; Purification of water for drinking purposes; Soft and hard water; Water pollution; Arsenic compounds and fluoride in groundwater.

Chapter 5. Energy in Action. Work Power and Energy
Work: Definition of work, W = F.D. Unit of work. Work done by and against the force. No workforce; Power: Definition of power, p = w/t. Unit of power; Energy: Definition of energy. Potential energy. Kinetic energy. Conservation of Mechanical Energy.

Chapter 6 Heat
Calorimetry: Principles of calorimetry. Heat gained = Heat lost; Equivalence of work and heat: W = J.H; Latent heat: Change of state; Saturated and unsaturated vapour: Saturated and unsaturated vapour; Anomalous expansion of water: Effects of anomalous nature of water on marine life.

Chapter 7 Sound
Sources of sound: Vibration: Sound is produced by vibration. Mechanism of sound production in the human vocal chord. Some quantities are related to vibration amplitude, period, and frequency; Propagation of sound Wave: Necessity of medium for sound propagation; Waves: Longitudinal and Transverse wave. Some physical quantities related to waves: are amplitude, wavelength, period, wave frequency, and wave velocity. Relation among wave frequency, wavelength, and wave velocity V = n.λ; Some properties of sound: Reflection of sound. Echo. Reverberation of sound; Audible sound and its frequency range. Ultrasonic sound. Uses of ultrasonic sound; Characteristics of Sound: Loudness. Pitch. Quality of Sound.
The human ear and mechanism of hearing sound: Structure (Human ear). Sound Propagation through the different parts of the ear; Sound Pollution: Sound Pollution and its remedy.

WBBSE Class 9 Physical Science Blueprint for 1st Summative Evaluation (Total Marks – 40)

 Theme/Sub-Theme MCQ (Group A) VSA (Group B) SA (Group C) LA (Group D) Total 1. Measurement 1 × 3 1 × 2 2 × 2 3 × 1 12 2. Force and Motion 1 × 2 1 × 3 2 × 3 3 × 1 14 3. Atomic Structure 1 × 3 1 × 2 2 × 3 3 × 1 14 Total 8 7 16 9 40

WBBSE Class 9 Physical Science Blueprint for 2nd Summative Evaluation (Total Marks – 40)

 Theme/Sub-Theme MCQ (Group A) VSA (Group B) SA (Group C) LA (Group D) Total 1. Mole Concept 1 × 2 1 × 1 2 × 1 3 × 1 8 2. Matter: Structure and Properties 1 × 2 1 × 3 2 × 1 3 × 1 10 3. Solution 1 × 1 1 × 1 2 × 1 3 × 1 7 4. Acids, Bases, Salts 1 × 2 1 × 1 2 × 1 3 × 1 8 5. Work, Power, Energy 1 × 1 1 × 1 2 × 1 3 × 1 7 Total 8 7 10 15 40

1. In Group A: All the Multiple Choice Questions (MCQ) are compulsory. There will be no alternative to any question in this Group.
2. In Group B: VSA will contain – (i) answer in a single word or a single sentence, (ii) column matching, (iii) fill in the blanks, and (iv) true/ false type questions. In the first & second summative, there will be alternatives to a total of 3 questions from the same theme/sub-theme.
3. In Group C: In the first & second summative there will be an alternative to 3 questions from the same theme/sub-theme.
4. In Group D: In the first & second summative there will be an alternative to 3 questions from the same theme/sub-theme. In this Group, 3 marks may be broken as (2 + 1).
5. All alternatives should be internal i.e. an alternative to question (2a) should be designed as (2a) [Question] OR [Question], (2b), etc.
6. Each numerical question will have an alternative item from the same theme/sub-theme.

WBBSE Class 9 Physical Science Blueprint for 3rd Summative Evaluation/Selection Test (Total Marks – 90)

 Section Theme/Sub-Theme MCQ (Group A) VSA (Group B) SA (Group C) LA (Group D) Total Physics 1. Matter: Structure and Properties 1 × 1 1 × 1 2 × 2 3 × 1 9 2. Measurement 1 × 1 1 × 2 2 × 1 – 5 3. Force and Motion 1 × 1 1 × 2 2 × 1 3 × 1 8 4. Work, Power, Energy 1 × 1 1 × 2 2 × 2 – 7 5. Sound 1 × 1 1 × 2 2 × 1 3 × 1 8 6. Heat 1 × 1 1 × 2 2 × 1 3 × 1 8 Chemistry 7. Atomic Structure 1 × 1 1 × 2 2 × 1 3 × 1 8 8. Mole Concept 1 × 1 1 × 2 2 × 1 3 × 1 8 9. Solution 1 × 1 1 × 2 2 × 1 3 × 1 8 10. Acids, Bases and Salts 1 × 2 1 × 2 2 × 1 3 × 1 9 11. Separation of Components of Mixtures 1 × 1 1 × 2 2 × 1 – 5 12. Water 1 × 1 1 × 2 2 × 2 – 7 Total 13 23 30 24 90  1. In Group A: All the Multiple Choice Questions (MCQ) are compulsory. There will be no alternative to any question in this Group.
2. In Group B: VSA will contain – (i) answer in a single word or a single sentence, (ii) column matching, (iii) fill in the blanks, (iv) true/ false type questions. In this group there will be alternatives to a total of 8 questions: alternative to 4 questions from Physics and 4 questions from Chemistry will be given. All alternatives will be from the same theme/sub-theme.
3. In Group C: (a) Eight (8) questions from Physics will have to be answered. There will be alternatives to 3 questions from the same theme, (b) Seven (7) questions from Chemistry will have to be answered. There will be an alternative to 3 questions from the same sub-theme.
4. In Group D: (a) Four (4) questions from Physics will have to be answered. There will be alternatives to 2 questions from the same theme, (b) Four (4) questions from Chemistry will have to be answered. There will be an alternative to 2 questions from the same sub-theme. In this Group, 3 marks may be broken as (2 + 1).
5. All alternatives should be internal i.e. an alternative to question (2a) should be designed as (2a) [Question] OR [Question], (2b), etc.
6. Each numerical question will have an alternative item from the same theme/sub-theme.