Class 9 Physical Science And Environment

• Chapter 1 Measurement
•  Chapter 2 Forces And Motion
• Chapter 3 Matter: Structure And Properties

• Chapter 4 Matter: Atomic Structure; Physical & Chemical Properties of Matter
  • 4.1 Atomic Structure 
  • 4.2 Concept Of Mole
    • 4.3 Solution 
    • 4.4 Acids, Bases And Salts
    • 4.5 Separation Of Components Of Mixture 
    • 4.6 Water
• Chapter 5 Energy In Action, Work, Power And Energy
• Chapter 6 Heat
• Chapter 7 Sound

Chapter 6 Heat MCQs

Question 1. Calorimetry relates to the measurement of

1. Heat
2. Temperature
3. Mechanical energy
4.  None of these

Answer: (1) Heat

Question 2. The quantity of heat in a body depends on its

1. Temperature
2. Mass
3. Material
4. All of them

Answer: (4) All of them

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. The quantity of heat is given by

1. \(\frac{\mathrm{ms}}{\mathrm{t}}\)
2.  mst
3. \(\frac{\mathrm{mt}}{\mathrm{s}}\)
4. \(\frac{\mathrm{st}}{\mathrm{m}}\)

Answer: (2) mst

Question 4. Work done W and heat produced H are related to each other (where J is the mechanical equivalent of heat

1. WH = J
2. H = JW
3.  W = JH
4.  WJH = 1

Answer: (3) W = JH

WBBSE Class 9 heat chapter MCQs with answers

Question 5. The value of the mechanical equivalent of heat (in erg/calorie) is

1. 4.2 x \(10^{-7}\)
2. 4.2 x \(10^{7}\)
3. \(\frac{1}{4.2}\)x \(10^{7}\)
4.  4.2

Answer: (2) 4.2 x \(10^{7}\)

Question 6. The latent heat of the fusion of ice is

1. 80 cal \(g^{-1}\)
2. 3.36 x 105 cal \(g^{-1}\)
3.  80 joule \(g^{-1}\)
4. 3.36 cal \(g^{-1}\)

Answer: (1) 80 cal \(g^{-1}\)

Question 7. Saturated vapour obeys

1.  Boyle’s law
2. Charles’ law
3. Pressure law
4.  None of these laws

Answer: (1) Boyle’s law

Question 8. Dews are formed at a temperature

1. Greater than dew point
2. Less than dew point
3. Equal to dew point
4.  Independent of dew point

Answer: (4) Independent of dew point

Question 9. The volume of water is minimal at a temperature

1.  − 4°C
2. 4°C
3.  o°C
4. 1°C

Answer: (3) 0°C

Heat multiple choice questions for WBBSE Class 9

Question 10. The thermal capacity of a body of mass m and specific heat s is

1. \(\frac{m}{s}\)
2. \(\frac{s}{m}\)
3. \(\frac{1}{\mathrm{~ms}}\)
4. ms

Answer: (4) ms

Question 11. What is the unit of heat in the SI system?

1. Calorie
2. Joule
3. Erg
4. Newton

Answer: (2) Joule

Question 12. Who designed the absolute scale of temperature?

1. Newton
2. Lord Kelvin
3. Celsius
4. Boyle

Answer: (2) Lord Kelvin

Important heat chapter questions for Class 9 Physical Science

Question 13. Which substance has the highest specific heat?

1. Water
2. Iron
3. Gold
4. Ice

Answer: (1) Water

Question 14. The fundamental interval of the Celsius scale is divided into divisions.

1. 100
2. 180
3. 120
4. 102

Answer: (1) 100

Question 15. The fundamental interval of the Fahrenheit scale is divided into divisions.

1. 180
2. 100
3. 32
4. 212

Answer: (1) 180

WBBSE Class 9 Physical Science MCQs on heat and temperature

Question 16. If C and F represent two particular temperatures of Celsius and Fahrenheit scales respectively, they are related is

1. \(\frac{C}{4}\)=\(\frac{F-32}{9}\)
2. \(\frac{C}{5}\)=\(\frac{F-32}{9}\)
3. \(\frac{C}{3}\)=\(\frac{F-32}{5}\)
4. \(\frac{C}{9}\)=\(\frac{F-32}{5}\)

Answer: (2)\(\frac{C}{5}\)=\(\frac{F-32}{9}\)

Question 17. The instrument measures the temperature of a body

1. Hydrometer
2. Thermometer
3.  Voltameter
4. Ammeter

Answer: (2) Thermometer

Question 18. How many calories of heat would be produced by converting 42 joules of work completely into heat?

1. 100 calories
2. 10 calories
3. 1000 calories
4. 90 calories

Answer: (2) 10 calories

Question 19. The normal body temperature of a man is 

1. 98.4°C
2.  98.4°F
3. 98.4 K
4. 100°F

Answer: (2) 98.4°F

Solved MCQs on heat for WBBSE Class 9

Question 20. Which substance has the highest specific heat?

1. Ethanol
2. Water
3. Acetone
4. Ether

Answer: (2) Water

Question 21. If the specific heat of copper is 0.09, what will be the water equivalent of a block of copper of mass 50 g?

1.  45g
2. 4.5 g
3. 450 g
4. 44g

Answer: (2) 4.5 g

Question 22. What is the melting point of ice in Fahrenheit scale?

1. 0°F
2. 32°F
3. 180°F
4. 20°F

Answer: (2) 32°F

Question 23. What is the specific heat of water in the SI system?

1. 42 joule
2. 4200 joule/kg
3. 4200 joule/kg K
4. 42,000 joule/kg

Answer: (3) 4200 joule/kg K

Modes of heat transfer MCQs Class 9 WBBSE

Question 24. The dimension of heat is

1. MLT
2. \(\mathrm{ML}^{2} \mathrm{~T}^{-2}\)
3. \(\mathrm{ML}^{-1} \mathrm{~T}^{-2}\)
4. \(\mathrm{ML}^{-1} \mathrm{~T}^{-1}\)

Answer: (2) \(\mathrm{ML}^{2} \mathrm{~T}^{-2}\)

Question 25. Generally, the body temperature of a man is measured on a scale.

1. Celsius
2. Fahrenheit
3. Kelvin
4.  Reumer

Answer: (2) Fahrenheit

Question 26. Heat reaches the earth from the sun by the process of 

1. Conduction
2. Convection
3. Radiation
4.  None of these

Answer: (3) Radiation

Question 27. The value of the mechanical equivalent of heat in the CGS system is

1.  4.18 x \(10^{7}\)erg/calorie
2. 4.8 erg/calorie
3. 5.18 x \(10^{7}\)erg/calorie
4. 5.18 erg/calorie

Answer: (1) 4.18 x \(10^{7}\)erg/calorie

Question 28. How much work is to be done to produce 50 calories of heat?

1. 210 joule
2. 200 joule
3. 20(1)joule
4.  310 joule

Answer: (1) 210 joule

Question 29. The water equivalent of a body is equal to

1.  Mass of the body x specific heat
2. Mass of the body/specific heat
3. Mass of the body + specific heat
4.  Mass of the body − specific heat

Answer: (1) Mass of the body x specific heat

Question 30. Mercury remains in a liquid state for a range of temperature 

1. − 39°C to 357°C
2. − 57°C to 457°C
3. − 10°C to 257°C
4. −12°C to 122°C

Answer: (1) −39°C to 357°C

Best multiple choice questions on heat for WBBSE Class 9

Question 31. — 40°C is equal to

1.  − 50°F
2.  − 40°F
3.  − 60°F
4. − 80°F

Answer: (2) − 40°F

Question 32. 1°F is equal to

1. \(\frac{5}{9}^{\circ} \mathrm{C}\)
2. \(\frac{9}{5}^{\circ} \mathrm{C}\)
3. \(\frac{8}{5}^{\circ} \mathrm{C}\)
4. \(\frac{7}{5}^{\circ} \mathrm{C}\)

Answer: (1)\(\frac{5}{9}^{\circ} \mathrm{C}\)

Question 33. (1)calorie is equal to

1. 4.18 Joule
2. 5.18 Joule
3.  3.18 Joule
4.  4.18 Joule

Answer: (1) 4.18 Joule

Question 34. If the temperature in the Kelvin scale is T K and the temperature on the Celsius scale is t°C, then they are related as

1.  T K = (273 + t °C)
2. T K = (273 −t °C)
3. T K = (273 t °C)
4. TK = 0°C

Answer: (1) T K = (273 + t °C)

Question 35. Vapour cools when it

1. Is kept under high pressure
2. Suddenly expands
3. Is confined in a closed vessel
4. It is heated

Answer: (2) Suddenly expands

Question 36. The calorimeter is made of

1. Glass
2. Iron
3. Aluminium
4. Copper

Answer: (1) Glass

Question 37. When ice is kept under higher pressure its melting point

1. Increases
2. Decreases
3. Remains unchanged
4. Fluctuates

Answer: (2) Decreases

Question 38. When the temperature of a room equals the dew point, then the relative humidity of the room becomes

1. 50%
2. Zero
3. 100%
4. 20%

Answer: (3) 100%

Question 39. The saturated vapour pressure of water at 100°C is

1.  78 cm
2. 72 cm
3. 76 cm
4. 60 cm

Answer: (3) 76 cm

Question 40. A large chunk of ice melts at its bottom not at its upper surface because

1. The bottom region exists at the surrounding temperature
2.  Impurities are present at the bottom
3. The weight of the ice exerts the surrounding pressure
4. Impurities are present at the upper surface

Answer: (3) The Weight of the ice exerts the surrounding pressure

Question 41. Water boils when its saturated pressure

Becomes high

Equals the surrounding pressure

Becomes very low

Is zero

Answer: (2) Equals the surrounding pressure

Question 42. Cooking at high altitudes is more difficult because of

1. High pressure
2. High pressure and high boiling point
3. Low pressure
4. Low pressure and high boiling point

Answer: (3) Low pressure

Question 43. At the same temperature, 1g iron melts more ice than 1g lead, because

1. The density of iron is greater than that of lead
2.  The specific heat of iron is more than that of lead
3. The latent heat of melting iron is more than that of lead
4.  Iron is heavier than lead

Answer: (2) Specific heat of iron is more than that of lead

Question 44. A piece of ice at 0°C is dropped in water at 0°C. The piece of ice

1. Will melt
2. Part of the ice will melt
3. Ice will not melt
4. 1% of the ice will not

Answer: (1) Will melt

WBBSE Class 9 Physical Science latent heat and specific heat MCQs

Question 45. 50 g ice at 0°C is mixed in 50 g water at 20°C. The final temperature of the mixture will be

1.  −10°C
2.  −30°C
3.  0°C
4. 10°C

Answer: (4) 10°C

Question 46. Which of the following has two specific nests 2

1. Solid
2. Gas
3. Liquid
4.  Solid, liquid and gas

Answer: (3) Liquid

Question 47. Two blocks of lead of masses M and 2M are at the same temperature; heat contained by the heavier block is

1. Half of that of M
2. Equal to that of M
3. Twice that of M
4.  Four times that of M

Answer: (3) Twice that of M

Question 48. Which pair among the following denote the same physical quantity?

1. Kelvin and Joule
2.  Kelvin and Calorie
3. Newton and Calorie
4. Joule and Calorie

Answer: (4) Joule and Calorie

Question 49. The specific heat of a metallic body depends on

1. Heat supplied to the body
2. Increase in the temperature of the body
3. Mass of the body
4. Material of the body

Answer: (4) Material of the body

Question 50. The volume of some water is minimal at

1.  100°C
2.  0°C
3.  4°C
4. −4°C

Answer: (3) 4°C

Question 51. The volume of water in the temperature range from 0°C to 4°C

1. Increases
2. Decreases
3. Remains the same
4. May either increase or decrease

Answer: (2) Decreases

Question 52. The coefficient of expansion of water in the range 0°C to 4°C is

1. Zero
2.  Negative
3. Positive
4. Infinity

Answer: (2) Negative

Question 53. Due to the special behaviour of water, lakes and ponds freeze

1. First at the bottom
2. First in the middle layer
3.  First at their surface
4. Anywhere

Answer: (3) First at their surface

Question 54. The amount of heat required to raise the temperature of a body depends on

1. The mass only
2.  The temperature
3. The specific heat only
4. All three of them

Answer: (4) All three of them

Question 55. By definition (1)cal is equal to

1. 1 J
2. \(\frac{1}{4.186}\)
3. 4.186 J
4. None

Answer: (3) 4.186 J

Question 56. For m = mass of calorimeter and s = specific heat or the calorimeter material, the water equivalent of the calorimeter is

1.  \(\frac{m}{s}\)
2. \(\frac{m}{s}\)
3. \(\mathrm{m}^2 s\)
4. ms

Answer: (2)\(\frac{m}{s}\)

Question 57. Water boils at a temperature T (when pressure is 1.5 atm)

1. T = 100°C
2. T < 100°C
3. T > 100°C
4. None

Answer: (3) T > 100°C

Question 58. The heat of vaporization of water at 100°C is

1. 4.186 J
2.  539 J/g
3. 539 cal/g
4. 80 cal/g

Answer: (3) 539 cal/g

 

Chapter 5 Energy In Action, Work, Power And Energy MCQs

Question 1. The rate of doing work is called

1. Velocity
2. Energy
3. Power
4. Force

Answer: (3) Power

Question 2. The unit of energy in SI system is

1. Erg
2. Watt
3. Horse power
4. Joule

Answer: (4) Joule

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. One watt is equal to

1. 1 erg/s
2. 1 g.cm/s
3. 1 kg.m/s
4. 1 joule/s

Answer: (4) 1 joule/s

Question 4. One horsepower is equal to

1. 500 W
2. 1000 W
3. 746 W
4. 764 W

Answer: (3) 746 W

WBBSE Class 9 work power and energy MCQs with answers

Question 5. Kilowatt is the unit of

1. Energy
2. Work done
3. Power
4. Force

Answer: (3) Power

Question 6. ln case of negative work, the angle between force and displacement is

1. 0°
2. 45°
3. 90°
4. 180°

Answer: (4) 180°

Question 7. In a tug-of-war, work done by the losing team is

1. Positive
2. Negative
3. Zero
4. None of these

Answer: (2) Negative

Work power and energy multiple choice questions for WBBSE Class 9

Question 8. The work done on an object does not depend upon the

1. Displacement
2. Initial velocity of the object
3. Force applied
4. Angle between force and displacement

Answer: (2) Initial velocity of the object

Question 9. Which one of the following is not a unit of energy?

1. Kilowatt
2. Joule
3. Newton-metre
4. Kilowatt-hour

Answer: (4) Kilowatt

Question 10. When an object falls freely under gravity, then its total energy

1. Increases
2. Decreases
3. Remains constant
4. First increases and then decreases

Answer: (3) Remains constant

Question 11. When a body moves in a circular path, everything remains unchanged except

1. Acceleration
2. Kinetic energy
3. Speed
4. Retardation

Answer: (2) Kinetic energy

Important work and energy questions for Class 9 Physical Science

Question 12. A body when raised from the floor to the top of a table, the work done depends on

1. Weight of the body
2. Time needed to raise it
3. Velocity of the body
4. Acceleration of the body

Answer: (1) Weight of the body

Question 13. A person while walking along a-road carrying a bag in hand, he does

1. Not do work on the bag
2. Work on the bag
3. Work on the bag if the bag be light
4. Work on the bag if the bag be heavy

Answer: (1) Not do work on the bag

Question 14. A mechanical system tends to attain the position of 

1. Maximum kinetic energy
2. Minimum kinetic energy
3. Minimum potential energy
4. Maximum potential energy

Answer: (3) Minimum potential energy

Question 15. A body of mass m when raised from.a depth h below the earth’s surface to a position h distance above the earth, the change of potential energy will be

1. 2 mgh
2. Zero
3. mgh
4. 3 mgh

Answer: (3) mgh

WBBSE Class 9 Physical Science MCQs on energy in action

Question 16. Newton meter is the unit of

1. Work in-SI
2. Power in SI
3. Power in SI
4. Work in CGS

Answer: (1) Work in SI

Question 17. Two bodies of masses 1 g and 4 g move with equal kinetic energy. Ratio of the magnitude of their momenta is

1. 4:1
2. \(\sqrt{2}\):1
3. 1:2
4. 1:16

Answer: (3) 1:2

Question 18. On application of an external force on a moving body, a body is retarded. Work done by the body is

1. Negative
2. Positive
3. Zero
4. Half

Answer: (1) Negative

Question 19. Due to winding of spring, a clock acquires

1. Kinetic energy
2. No energy
3. Elastic potential energy
4. Gravitational potential energy

Answer: (3) Elastic potential energy

Question 20. To obey the law of conservation of linear momentum during collision a condition is

1. External force is 0
2. Time of collision is negligible
3. No internal force
4. External force is maximum

Answer: (1) External force is 0

Solved MCQs on work, power, and energy for WBBSE Class 9

Question 21. A raindrop of radius R fell on ground from a height h. Work done by the gravitational force is proportional to

1. \({R}^{}\)
2. \(\sqrt{R}\)
3. \({R}^{3}\)
4. \({R}^{2}\)

Answer: (3) \({R}^{3}\)

Question 22. A body is moved from a point A to point B over a rough surface that possesses friction due to which x work is done. The pedy moves back from B to A on the same surface. Total work done will be

1. Zero
2. x
3. 2x
4. 3x

Answer: (3) 2x

Question 23. Which pair of physical quantities have same unit?

1. Force and work
2. Work and energy
3. Power and force
4. Work and power

Answer: (2) Work and energy

Question 24. Increase of kinetic energy equals

1. Increase of mass
2. Work done
3. Increase of power
4. Increase of velocity

Answer: (2) Work done

Question 25. Two bodies of different masses have equal kinetic energy. Momentum possessed by

1. The body of less mass is larger
2. The body of larger mass is larger
3. Both the bodies are equal
4. The body of larger velocity is larger

Answer: (2) The body of larger mass is larger

Question 26. Work is done when the point of application of force moves

1. Perpendicular to the force
2. In the direction of force
3. In any direction
4. In the direction perpendicular to force

Answer: (2) In the direction of force

Law of conservation of energy MCQs Class 9 WBBSE

Question 27. Water reserved in a dam possesses

1. Kinetic energy
2. Potential energy
3. Both potential and kinetic energies
4. No energy

Answer: (2) Potential energy

Question 28. A person performs 300 J work in 1.5 hr. Another person does 1500 J in 100 hr. The power of

1. 1st person is greater
2. 2nd person is greater
3. Both the person are equal
4. Both are zero

Answer: (1) 1st person is greater

Question 29. SI unit of energy is

1. Joule
2. Erg
3. Dyne
4. Newton

Answer: (1) Joule

Question 30. The potential energy of a boy is maximum when he is

1. Sitting on the floor
2. Standing on the floor
3. Sleeping on the floor
4. Sitting on a chair

Answer: (2) Standing on the floor

Question 31. Water stored in a dam possesses

1. KE
2. PE
3. Electric energy
4. No energy

Answer: (2) PE

Question 32. The kinetic energy of an object is K. If its mass is reduced to half, then its kinetic energy will be

1. K
2. 2K
3. K/2
4. K/4

Answer: (3) K/2

Question 33. The work done on an object does not depend upon the 

1. Force applied
2. Initial velocity
3. Displacement
4. Angle between force and displacement

Answer: (2) Initial velocity

Question 34. In case of negative work, the angle between force and displacement is

1. 0°
2. 45°
3. 90°
4. 180°

Answer: (4) 180°

Question 35. In a tug-of-war, work done by the losing team is

1. Zero
2. Positive
3. Negative
4. None of these

Answer: (3) Negative

Best multiple choice questions on work power and energy for WBBSE Class 9

Question 36. A stone is thrown vertically upwards. It comes to rest momentarily at the highest point. What happens to its kinetic energy?

1. It is converted into elastic potential energy
2. It is converted into gravitational potential energy
3. It is converted into chemical energy
4. It is completely destroyed

Answer: (2) It is converted into gravitational potential energy

Question 37. A force of 100 N acting on a body 1000 J work. The distance through which the body is displaced is

1. 5m
2. 10 cm
3. 10m
4. 55cm

Answer: (2) 10 m

Question 38. When electric current passes through an electric bulb, electric energy is converted into

1. Heat energy only
2. Light energy only
3. Both heat and light energy
4. Both light and chemical energy

Answer: (3) Both heat and light energy

Question 39. What type of energy a raised hammer possesses?

1. Kinetic energy
2. Potential energy
3. Gravitational energy
4. No energy

Answer: (2) Potential energy

Question 40. What is the absolute unit of work in SI system?

1. 1 kg-m
2. 1 joule
3. 1 erg
4. 1 dyne

Answer: (2) 1 joule

Question 41. What is the relation between power and force?

1. Power = force x velocity
2. Velocity = force x power
3. Force = power x velocity
4. Power = force/2

Answer: (1) Power = force x velocity

Question 42. What is the amount of work performed by a person on the weight w that he carries and moves horizontally through a distance d?

1. No work is done
2. Work done = w xd
3. Work done = w ÷ d
4. Work done \(=\frac{d}{w}\)

Answer: (1) No work is done

Question 43. The dimension of energy is

1. \(\left[\mathrm{ML}^2 \mathrm{~T}^{-2}\right]\)
2. \(\left[\mathrm{M}^2{L}^2 \mathrm{~T}^{3}\right]\)
3. \(\left[\mathrm{ML}^2 \mathrm{~T}^{3}\right]\)
4. \(\left[\mathrm{ML}^3 \mathrm{~T}^{2}\right]\)

Answer: (1) \(\left[\mathrm{ML}^2 \mathrm{~T}^{-2}\right]\)

Question 44. All energies are transformed ultimately into

1. Heat energy
2. Kinetic energy
3. Sound energy
4. Electric energy

Answer: (1) Heat energy

Question 45. Which one is a scalar quantity?

1. Force
2. Displacement
3. Work
4. Velocity

Answer: (3) Work

Question 46. If the velocity of a body is doubled then kinetic energy will be

1. Same
2. Doubled
3. Four times
4. Halved

Answer: (3) Four times

Question 47. Work done in unit time is known as

1. Power
2. Energy
3. Force
4. Velocity

Answer: (1) Power

Question 48. 1 kilowatt =

1. \(\frac{2}{3}\) HP
2. \(\frac{4}{3}\) HP
3. \(\frac{7}{3}\) HP
4. \(\frac{1}{3}\) HP

Answer: (2) \(\frac{4}{3}\) HP

WBBSE Class 9 Physical Science kinetic and potential energy MCQs

Question 49. What is the unit of kinetic energy is SI system?

1. Erg
2. HP
3. Joule
4. Dyne

Answer: (3) Joule

Question 50. 1 mega-watt =

1. \({10}^3\) watt
2. \({10}^4\)watt
3. \({10}^6\)watt
4. \({10}^2\) watt

Answer: (3) \({10}^6\)watt

Question 51. Kilogram-metre is the unit of

1. Energy
2. Power
3. Work
4. Velocity

Answer: (3) Work

Question 52. The dimension of power is

1. \(\left[\mathrm{ML}^2 \mathrm{~T}^{-3}\right]\)
2. \(\left[\mathrm{M}^2{L}^2 \mathrm{~T}^{-2}\right]\)
3. \(\left[\mathrm{ML}^3 \mathrm{~T}^{3}\right]\)
4. \(\left[\mathrm{ML}^2 \mathrm{~T}^{3}\right]\)

Answer: (1) \(\left[\mathrm{ML}^2 \mathrm{~T}^{-3}\right]\)

Question 53. 1 watt =

1. \({10}^5\) erg/sec
2. \({10}^6\) erg/sec
3. \({10}^7\) erg/sec
4. \({10}^8\) erg/sec

Answer: \({10}^7\) erg/sec

Question 54. What is the practical unit of power in CGS system?

1. Erg
2. Watt
3. Joule
4. Newton

Answer: (2) Watt

 

Chapter 3 Matter: Structure And Properties MCQs

Question 1. Atmospheric pressure is measured by 

1. Hygrometer
2. Pyrometer
3. Barometer
4. Spherometer

Answer: (3) Barometer

Question 2. Construction of a submarine is based on 

1. Archimedes’ principle
2. Bernoulli’s theorem
3. Pascal’s law
4. Boyle’s law

Answer: (1) Archimedes’ principle

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. Why is the dam of water reservoir thick at the bottom?

1. Quantity of water increases with depth
2. Density of water increases with depth
3. Pressure of water increases with depth
4. Temperature of water increases with depth

Answer: (3) Pressure of water increases with depth

WBBSE Class 9 matter structure and properties MCQs with answers

Question 4. A wooden block is taken to the bottom of a deep, calm lake and then released. It rises up with a

1. Constant acceleration
2. Decreasing acceleration
3. Constant velocity
4. Decreasing velocity

Answer: (3) Constant acceleration

Question 5. A capillary tube made of glass is dipped into mercury. Then

1. Mercury rises in the capillary tube
2. Mercury falls in the capillary tube
3. Mercury rises and flows out of the capillary tube
4. Mercury neither rises nor falls in the capillary tube.

Answer: (2) Mercury falls in the capillary tube

Question 6. If the diameter of a capillary tube be doubled then the height of the liquid that will rise is

1. Twice
2. Half
3. Same as earlier
4. None

Answer: (2) Half

Question 7. Two pieces of glass plates, one upon the other, with a little water in between them cannot be separated easily because of 

1. Inertia
2. Pressure
3. Surface tension
4. Viscosity

Answer: (3) Surface tension

Matter structure and properties multiple choice questions for WBBSE Class 9

Question 8. There is dip in the capillary tube when the angle of contact 6 is 

1. θ= 90°
2. θ= 0°
3. θ> 90°
4. θ< 90° but not zero

Answer: (4) θ< 90° but not zero

Question 9. The rise of liquid in a capillary tube has a meniscus. If the angle of contact be 90°, the shape of the meniscus is 

1. Concave
2. Convex
3. Flat
4. None

Answer: (3) Flat

Question 10. In Bernoulli’s theorem, which of the following is conserved?

1. Mass
2. Linear momentum
3. Energy
4. Angular momentum

Answer: (3) Energy

Question 11. The gale blows over a house. The force due to gale on the roof is 

1. In the direction downward
2. In direction upward
3. Zero
4. In the horizontal direction

Answer: (1) In direction upward

Important matter structure questions for Class 9 Physical Science

Question 12. To calculate the flow of a liquid, which of the following is used?

1. Stoke’s law
2. Bernoulli’s theorem
3. Poisseuille’s law
4. Conservation of pressure

Answer: (3) Poisseuilie’s law

Question 13. In old age arteries carrying blood in the human body become narrow resulting in an increase in the blood pressure. This follows from

1. Pascal’s law
2. Stoke’s law
3. Bernoullis’ principle
4. Archimedes’ principle

Answer: (3) Bernoullis’ principle

Question 14. On which of the following the terminal velocity of a solid ball in a viscous fluid’ is dependent?

1. Area f cross-section
2. Height of the liquid
3. Density of both
4. Density of the liquid

Answer: (2) Height of the liquid

Question 15. A body of weight mg is hanging on a strain, which extends its length by I. The work done in extending the string is

1. mgl
2. mgl/2
3. 2mgl
4. None of these

Answer: (2) mgl/2

Question 16. Scent sprayer is based on

1. Charle’s law
2. Archimedes’ principle
3. Boyle’s law
4. Bernoulli’s theorem

Answer: (4) Bernoulli’s theorem

WBBSE Class 9 Physical Science MCQs on states of matter

Question 17. According to Hooke’s law of elasticity, if stress is increased the ratio of stress to strain

1. Increases
2. Decreases
3. Becomes zero
4. Remains constant

Answer: (4) Remains constant

Question 18. When a body remains immersed in water its weight

1. Increases
2. Remains same
3. Decreases
4. None of these

Answer: (2) Remains same

Question 19. When a body weights more than that of the liquid displaced by it, the mildly

1. Floats
2. Sinks
3. Partly floats
4. Partly sinks

Answer: (2) Sinks

Question 20. Artesian well works on the principle of

1. Liquid finds its own level
2. Buoyancy
3. Newton’s Third law
4. Conservation of linear momentum

Answer: (1) Liquid finds its own level

Solved MCQs on matter and its properties for WBBSE Class 9

Question 21. Lower part of a ship sinks more when the ship enters from

1. Sea-to-river water
2. River water to sea water
3. Both (1) and (2)
4. None of these

Answer: (1) Sea-to-river water

Question 22. Lowermost layer of the atmosphere is

1. Troposphere
2. Stratosphere
3. Ionosphere
4. None of these

Answer: (1) Troposphere

Question 23. When the weight of a body is equal to the weight of the liquid displaced by it, the body

1. Floats partly immersed
2. Floats totally immersed
3. Sinks completely
4. Floats half immersed

Answer: (4) Floats totally immersed

Question 24. When the weight of a body is less than the weight of the liquid displaced by it the body

1. Floats parties immersed
2. Floats totally immersed
3. Sinks completely
4. Floats half immersed

Answer: (1) Floats partly immersed

Question 25. A boat floats in water because water exerts

1. Downward pressure
2. Lateral pressure
3. Vertical downward thrust
4. No pressure

Answer: (3) Vertical downward thrust

Question 26. The buoyancy of a liquid is its

1. Lateral thrust
2. Vertical downward thrust
3. Vertical upward thrust
4. Volume displaced by a solid

Answer: (2) Vertical downward thrust

Question 27. The immersed portion of a piece of ice in water is

1. 8/9th of its volume
2. 9/10th of its volume
3. 1/11th of its volume
4. 11/12th of its volume

Answer: (4) 11/12th of its volume

Physical and chemical properties of matter MCQs Class 9 WBBSE

Question 28. It is easier to swing in sea water than in a pond because

1. Sea water is never still
2. Atmospheric pressure is highest at the sea level
3. Density of seawater is higher than that of ordinary water.
4. None of these reasons are correct.

Answer: (3) Density of seawater is higher than that of ordinary water.

Question 29. A sinker weights 45 g-wt in air and 25 g-wt in water, the upthrust on it is

1. 25 g-wt
2. 45 g-wt
3. 20 g-wt
4. None of these

Answer: (3) 20 g-wt

Question 30. S.1. unit of pressure is

1. Pascal
2. kg/\(m^{-2}\)
3. Atmosphere
4. None of these

Answer: (1) Pascal

Question 31. Upthrust depends upon

1. Volume
2. Density
   
3. g
   
4. All of these

Answer: (4) All of these

Question 32. If the density of the object placed in a liquid is equal to the density of the liquid, the object will

1. Float wholly immersed
2. Float half immersed
3. Sink
4. Float completely above the liquid

Answer: (2) Float wholly immersed

Question 33. Atmospheric pressure is measured by

1. Hydrometer
2. Barometer
3. Sonometer
4. Ammeter

Answer: (2) Barometer

Question 34. The relative density s of a substance is related to the density of the substance Ppand density of water at 4°C d. The exact relation between them is

1. s=pxd
2. s\(=\frac{d}{\rho}\)
3. s\(=\frac{\rho}{d}\)
4. s\(=\frac{1}{\rho d}\)

Answer: (3)s\(=\frac{\rho}{d}\)

Question 35. SI unit of surface tension is

1. Nm
2. kgf\(m^{-1}\)
3. m\(N^{-1}\)
4. N\(m^{-1}\)

Answer: (4) N\(m^{-1}\)

Question 36. The terminal velocity of a spherical body depends on

1. Radius of the body
2. Density of the medium
3. Viscosity of the medium
4. All of these

Answer: (4) All of these

Best multiple choice questions on matter structure and properties for WBBSE Class 9

Question 37. Bernoulli’s theorem is based on the conservation of

1. Mass
2. Mass and energy
3. Energy
4. None of these

Answer: (3) Energy

Question 38. With increase of temperature, the elasticity of a material

1. Increases
2. Decreases
3. Remains unchanged
4. Nothing can be said

Answer: (2) Decreases

Question 39. The solids which break soon after crossing elastic limit are called

1. Ductile
2. Brittle
3. Malleable
4. Plastic

Answer: (2) Brittle

Question 40. Dimension of density is

1. M\(L^{-2}\)
2. M\(L^{-3}\)
3. L\(T^{-3}\)
4. M\(L^{-4}\)

Answer: (2) M\(L^{-3}\)

Question 41. S.1. unit of pressure is

1. N
2. N/\(m^{2}\)
3. N.m
4. N/m

Answer: (4) N/\(m^{2}\)

Question 42. A body floats in a liquid contained in a beaker. The whole system falls freel under gravity. The upward thrust on the body due to the liquid then is

1. Zero
2. Equal to the liquid displaced
3. Equal to the weight of the body in air
4. Equal to the weight of the immersed portion in the liquid

Answer: (1) Zero

Question 43. Clouds float in the atmosphere on account of their

1. Low viscosity
2. Low density
3. Low temperature
4. Creation of low pressure

Answer: (2) Low density

WBBSE Class 9 Physical Science atomic structure and bonding MCQs

Question 44. After terminal velocity is reached, the acceleration of a body falling through a fluid is

1. Equal to g
2. Zero
3. Less than g
4. More than g

Answer: (2) Zero

Question 45. The property by virtue of which a fluid tries to prevent the relative motion between adjacent layers is called

1. Elasticity
2. Rigidity
3. Viscosity
4. Cohesion

Answer: (3) Viscosity

Question 46. The pressure energy per unit weight of a liquid is

1. \(\frac{p}{\rho}\)
2. P
3. P\(. \rho\)
4. \(\frac{\rho}{p}\)

Answer: (1)\(\frac{p}{\rho}\)

Question 47. Which one of the following substances has the greatest velocity?

1. Water
2. Mercury
3. Oxygen
4. Hydrogen

Answer: (2) Mercury

Question 48. A drop of liquid is assumed to be spherical shaped because of

1. Density
2. Viscosity
3. Gravitation
4. Surface tension

Answer: (4) Surface tension

Question 49. The modulus of elasticity is dimensionally equivalent to

1. Stress
2. Strain
3. Directly proportional to strain
4. Inversely proportional to strain

Answer: (3) Directly proportional to strain

 

Chapter 2 Forces And Motion MCQs

Question 1. Definition of force is obtained from Newton’s

1. First law of motion
2. Second law of motion
3. Law of Gravitation
4.  Third law of motion

Answer: (1) First law of motion

Question 2. Measurment of force is obtained from Newton’s

1. Law of gravitation
2. 1st law of motion
3. Third law of motion
4. 2nd law of motion

Answer: (4) 2nd law of motion

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. Momentum is the product of mass and

1. Force
2. Time
3. Velocity
4. Speed

Answer: (3) Velocity

WBBSE Class 9 forces and motion MCQs with answers

Question 4. A ball rolling on floor stops because

1. Floor exerts a frictional force
2. Gravity
3. Absence of unbalanced force
4. None of these

Answer: (1) Floor exerts a frictional force

Question 5. A force 2F acts on a body creating acceleration a; the mass of the body is

1. F/a
2. 2F/a
3. 2Fxa
4. F/2a

Answer: (2) 2F/a

Question 6. A force acts on body at rest, distance moved by the body in time t is proportional to

1. \(t^2\)
2. t
3.  \(t^{-1}\)
4.  \(t^3\)

Answer: (1) \(t^2\)

Question 7. If a body is in acceleration then

1. Its speed always increases
2. Its velocity always increases
3. Its velocity always decreases
4.  A force acts on it

Answer: (2) Its velocity always increases

Forces and motion multiple choice questions for WBBSE Class 9

Question 8. Due to action of an unbalanced force on a body, the acceleration of the body is proportional to

1. The force acting on the body
2. Velocity of the body
3. Mass of the body
4. Speed of the body

Answer: (1) The force acting on the body

Question 9. Newton’s third law of motion may be applied to a body

1. Only at rest
2. Only in motion
3.  Both at rest and in motion
4.  None of these

Answer: (3) Both at rest and in motion

Question 10. Two bodies X and Y have masses of 20 kg and 90 kg respectively. Which of the two have more inertia?

1. Body x
2. Body Y
3. Both have equal inertia
4. None of these

Answer: (1) Body x

Question 11. Velocity of a particle moving with uniform acceleration

1. Decreases
2. Increases
3. Remains unaltered
4. None of these

Answer: (2) Increases

Important forces and motion questions for Class 9 Physical Science

Question 12. A man moving around a square field, each side of which is 50 m in length, returns to the starting point. His displacement is

1. 200 m
2. 50 m
3.  0m
4. 100 m

Answer: (3) 0m

Question 13. A particle moving in a circular path with uniform speed has an acceleration

1. Away from the center
2. Towards the center
3. Along the tangent at any point on a surface
4. None of these

Answer: (2) Towards the center

Question 14. If a body covers equal distances in equal time intervals, then it is

1. At rest
2. Moving with uniform speed
3. Moving with uniform velocity
4. Moving with uniform acceleration

Answer: (2) Moving with uniform speed

Question 15. If a body moves with a constant speed, the distance-time graph is

1. A straight line
2. A circle
3. A line like a staircase
4. A polygon

Answer: (1) A straight line

Question 16. The area under the speed-time graph is

1. Circle
2. Parabola
3. Distance
4. None of these

Answer: (3) Distance

WBBSE Class 9 Physical Science MCQs on Newton’s laws of motion

Question 17. The slope of a distance-time graph is

1. Velocity
2. Acceleration
3. Displacement
4. Speed

Answer: (4) Speed

Question 18. When a bus suddenly starts, the standing passengers lean backward in the. Bus, it is due to

1. Newton’s first law
2. Newton’s second law
3. Newton’s third law
4. None of these

Answer: (1) Newton’s first law

Question 19. The momentum of a body of given mass is proportional to its

1. Volume
2. Shape
3. Speed
4. Density

Answer: (3) Speed

Question 20. Which of the following has the largest inertia?

1. A pin
2. Your body
3. An orange
4. A brick

Answer: (2) Your body

Question 21. In absence of a force a body

1. Can be at rest
2. Moves with uniform speed
3. Continues in its state of rest of motion
4. (1) (2), (3), (4) all are correct

Answer:(4) (1) (2), (3), (4) all are correct

Solved MCQs on forces and motion for WBBSE Class 9

Question 22. Velocity is a

1. Vector
2. Scalar
3. Both
4. None

Answer: (1) Vector

Question 23. A body acted upon by a force must have

1. Velocity
2. Displacement
3. Acceleration
4. None of these

Answer: (3) Acceleration

Question 24. A body whose momentum is constant must have constant 

1. Force
2. Velocity
3.  Acceleration
4. All of these

Answer: (2) Velocity

Question 25. The motion of a rocket is based on the principle of conservation of

1. Mass
2. Kinetic energy
3. Linear momentum
4. Angular momentum

Answer: (3) Linear momentum

Question 26. A force of 250 N acts on a body and the momentum acquired by it is 125 kg m/s. What is the time for which the force acts on the body?

1. 0.2’s
2. 0.5s
3. 0.4s
4. 0.25 s

Answer: (2) 0.5 s

Laws of motion and inertia MCQs Class 9 WBBSE

Question 27. A scooter of mass 200 kg is moving with a uniform velocity of 18 km/h. The force required to stop the vehicle in 10 s is

1.  720 N
2.  360 N
3. 180 N
4. 216 N

Answer: (2) 360 N

Question 28. A body is moving with a constant speed in a straight line path. A force is not required to

1. Increase its speed
2. Change the direction
3. Decrease the momentum
4. Keep it moving with uniform velocity

Answer: (4) Keep it moving with uniform velocity

Question 29. A cricket player catches a ball of mass 0.1 kg moving with a speed of 10 m/s in 0.1 s. Force exerted by him is

1. 10 N
2. 5N
3. 2N
4. 1N

Answer: (1) 10 N

Best multiple choice questions on forces and motion for WBBSE Class 9

Question 30. What force will change the velocity of a body of mass 1 kg from 20 m/s to 30 m/ sin 2s?

1. 25 N
2. 5N
3. 10 N
4. 2N

Answer: (2) 5N

Question 31. The rocket engine lifts a rocket from the earth because hot gases with high

1. Push it against the earth
2. Push is against the air
3. React against the rocket and push it up
4. Heat the air which lifts the rocket

Answer: (3) React against the rocket and push it up

WBBSE Class 9 Physical Science friction and motion MCQs

Question 32. A man is at rest in the middle of a pond on perfectly smooth ice. He can get himself to the shore by making use of Newton’s

1.  First law
2. Second law
3. Third law
4. All the laws

Answer: (3) Third law

Question 33. A body of mass 2 kg is moving with a velocity of 8 m/s on.A smooth surface. If it is to be brought to rest in 4 s, then force to be applied is

1.  8N
2. 4N
3. 2N
4. 1N

Answer: (2) 4N

 

Chapter 7 Sound MCQs

Question 1. Sound can not travel through

1. Air
2. Water
3. Steel
4. Vacuum

Answer: (4) Vacuum

Question 2. Which frequencies are not audible to the human ear?

1. 30 Hz
2. 3000 Hz
3. 300 Hz
4. 30,000 Hz

Answer: (4) 30,000 Hz

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. The frequency of sound waves can be expressed in

1. Hz
2. dB
3. m
4. m/s

Answer: (1) Hz

WBBSE Class 9 sound chapter MCQs with answers

Question 4. Frequency (n) and period (T) are related as

1. \(\frac{n}{T}\)=1
2. n×T=1
3. n=\(\mathrm{T}^2\)
4. n\(\mathrm{T}^2\)=1

Answer: (2)

Question 5. The audible range of frequency in Hz is

1. 20 to 20,000
2. 2000 to 20,000
3. 40 to 4000
4. 200 to 2000

Answer: (1) 20 to 20,000

Question 6. Earthquake produces

1. Audible sound
2. Ultrasound
3. Infrasonic sound
4. None of these

Answer: (3) Infrasonic sound

Question 7. In SONAR, we use

1. Radio waves
2. Ultrasonic waves
3. Infrasonic waves
4. Audible sound waves

Answer: (2) Ultrasonic waves

Sound multiple choice questions for WBBSE Class 9

Question 8. Due to the increase in the frequency of the sounding source, its pitch

1. Increases
2. Decreases
3. Remains the same
4. First increases and then decreases

Answer: (1) Increases

Question 9. Stethoscope works on the principle of

1. Reflection of sound
2. Refraction sound
3. Reverberation of sound
4. None of these

Answer: (1) Reflection of sound

Question 10. The relation between velocity (v) of sound, wavelength (λ), and frequency (n) is

1. n\(=\frac{v}{\lambda}\)
2. λ=vm
3. n= λv
4. n\(=\frac{v^2}{\lambda}\)

Answer: (1) n\(=\frac{v}{\lambda}\)

Question 11. The velocity of sound in dry air at 0°C is

1. 233 m/s
2. 330 m/s
3. 332 m/s
4. 200 m/s

Answer: (3) 332 m/s

Important sound chapter questions for Class 9 Physical Science

Question 12. The minimum distance of the reflector creating an echo of a transient sound is

1. 33m
2. 16.6 m
3. 33 cm
4. 10m

Answer: (2) 16.6 m

Question 13. Propagation of sound requires

1. No medium
2. Material medium
3. Only gaseous medium
4. Aqueous medium

Answer: (2) Material medium

Question 14. Echo of sound is caused by

1. Violent sound
2. Flow of air
3. Reflection of sound
4. Refraction of sound

Answer: (3) Reflection of sound

Question 15. The unit of intensity of sound is

1. Hertz
2. m/\(s^2\)
3. Decibel
4. Dyne

Answer: (3) Decibel

WBBSE Class 9 Physical Science MCQs on sound waves

Question 16. Due to the propagation of a longitudinal wave through a medium, particles of the medium vibrate

1. Along and perpendicular to the direction of the wave
2. In all directions
3. Along the direction of the wave
4. Within a liquid

Answer: (3) Along the direction of the wave

Question 17. A transverse wave is produced in

1. Gas only
2. A liquid
3. In gas, solid and liquid
4. Solid only

Answer: (3) In gas, solid and liquid

Question 18. Distance traveled by a wave in one second is its

1. Velocity
2. Wavelength
3. Period
4. Frequency

Answer: (1) Velocity

Question 19. The correct formula is

1. v\(=1 / T\)
2. v=nλ
3. \(=\frac{v}{\lambda}\)
4. v=\(\mathrm{n}_2\).λ

Answer: (2) v=nλ

Solved MCQs on sound for WBBSE Class 9

Question 20. The loudness of the sound depends on

1. Wavelength of sound
2. Volume of air around the source of sound
3. Time of day
4. Reflection of sound

Answer: (1) Wavelength of sound

Question 21. The human ear is sensitive normally between the frequencies

1. 20-20,000 Hz
2. 10-100 Hz
3. 1-10 Hz
4. Above 20,000

Answer: (1) 20-20,000 Hz

Question 22. For hearing echo the minimum time difference between the direct and the reflected sound should be

1. 1/5 sec
2. 1/10 sec
3. 1 sec
4. 2 sec

Answer: (2) 1/10 sec.

Question 23. For a sound of wavelength 10 cm and frequency 10 created in a medium, the velocity of a sound wave is

1. 10 cm/sec
2. 100 cm/sec
3. 5 cm/sec
4. 20 cm/sec

Answer: (2) 100 cm/sec

Question 24. The surface of a wall can reflect sound waves and not light waves because

1. Sound has bigger wavelength
2. The wall is large
3. Sound has less velocity
4. Sound has bigger velocity

Answer: (1) Sound has bigger wavelength

Question 25. Elastic transverse waves can propagate through

1. Gaseous medium not through solid medium
2. Neither gaseous nor solid medium
3. Solid and gaseous medium
4. Solid medium, not through gaseous medium

Answer: (4) Solid medium, not through gaseous medium

Question 26. Repeated reflection of sound produces

1. Stationary wave
2. Echo
3. Reverberation
4. Refraction

Answer: (2) Echo

Question 27. The velocity of a sound wave of wavelength 1 in a medium is v, The wavelength of the wave in the medium of the velocity is 4 v, is

1. λ/2
2. 2/λ
3. 4/λ
4. 2/λ

Answer: (3) 4/λ

Question 28. The difference in intensity between two sound waves is 1 Bel. It means that the ratio of their intensities is

1. 5:1
2. 105
3. 1:4
4. 100: 4

Answer: (3) 1:1

Question 29. Which of the following is not true?

1. Sound waves do not propagate in straight lines
2. Sound wave carries energy
3. Sound waves travel faster in a vacuum than in air
4. Sound waves propagate in straight lines

Answer: (3) Sound waves travel faster in vacuum than in air

Reflection and refraction of sound MCQs Class 9 WBBSE

Question 30. The pitch of a note depends on the

1. Frequency
2. Velocity of sound
3. Wavelength of sound
4. Amplitude of wave

Answer: (3) Wavelength of sound

Question 31. The velocity of sound is greatest in

1. Mercury
2. Water
3. Steel
4. Air

Answer: (3) Steel

Question 32. The sound of thunder is heard after 5.5 sec after the flash. If the velocity of sound in air is 330 m/sec, the distance of the thunder is

1. 18.15 km
2. 1.815 km
3. 0.1815 km
4. 181.5 km

Answer: (2) 1.815 km

Question 33. A person fires a pistol standing between two hills. He hears echoes at 1-sec intervals. If the velocity of sound in air is 340 m/sec, the distance between the mountains is

1. 340 m
2. 170 m
3. 510 m
4. 66 m

Answer: (2) 170 m

Question 34. The characteristic by which two sounds of the same frequency and loudness can be differentiated is

1. Velocity of sound
2. Quality
3. Pitch
4. Medium in which the sound travels

Answer: (3) Pitch

Question 35. When a wave travels from one medium to another, the parameter of the wave
remaining unchanged is

1. Quality
2. Velocity
3. Frequency
4. Wavelength

Answer: (1) Quality

Question 36. What should be the minimum frequency of a vibrating body producing sound?

1. 2000 Hz
2. 100 Hz
3. 20 Hz
4. 150 Hz

Answer: (3) 20 Hz

Best multiple choice questions on sound for WBBSE Class 9

Question 37. How does the pitch of sound depend on frequency?

1. Pitch increases with a decrease in frequency
2. Pitch decreases with increase in frequency
3. Pitch increases or decreases accordingly with an increase or decrease in frequent
4. Pith remains constant

Answer: (3) Pitch increases or decreases accordingly with increase or decrease in frequency.

Question 38. The Unit Of Frequency is

1. ohm
2. mho
3. Hz
4. Torr

Answer: (3) Hz

Question 39. Migraine is caused by

1. Sound pollution
2. Air pollution
3. Water pollution
4. Land pollution

Answer: (1) Sound pollution

Question 40. When one end of a long iron pipe is struck, sounds are heard.

1. Two
2. Three
3. Four
4. One

Answer: (1) Two

Question 41. The relation between the velocity (v) of sound and its density (d) is 

1. \(v \propto \frac{1}{d}\)
2. \(v \propto \frac{1}{\sqrt{d}}\)
3. \(\frac{1}{d}\)
4. V α T

Answer: (2)\(v \propto \frac{1}{\sqrt{d}}\)

Question 42. The relation between the velocity (v) of sound with the absolute temperature (T) is

1. v α \(\sqrt{T}\)
2. v α T
3. v=T
4. v= \(\sqrt{T}\)

Answer: (1) v α \(\sqrt{T}\)

Question 43. If the size of the sounding body is bigger then the intensity of the sound will be

1. Increased
2. Decreased
3. Same
4. Constant

Answer: (1) Increased

Question 44. The velocity of sound through iron is then the velocity of sound through air.

1. 4 times
2. 10 times
3. 15 times
4. 5 times

Answer: (3) 15 times

WBBSE Class 9 Physical Science speed of sound MCQs

Question 45. The sensation due to sound lasts for about

1. \(\frac{1}{20}\) second
2. \(\frac{1}{10}\) t second
3. \(\frac{1}{30}\) Secon
4. \(\frac{1}{5}\) secon

Answer: (2) \(\frac{1}{10}\) second

Question 46. If the wave length is and the velocity of sound 1.7 m is 340 m/sec then what will be the wave frequency?

1. 20 Hz
2. 200 Hz
3. 2000 Hz
4. 2 Hz

Answer: (2) 200 Hz

Question 47. What is the fundamental tone if the tones in a note are of 100, 150, 200, 280, 300, 450, and 500?

1. 100
2. 280
3. 500
4. 450

Answer: (1) 100

Question 48. The sound of lightning is heard 6 sec after it is seen. If the velocity of sound is 330 m/sec at that time, what will be the distance of the cloud?

1. 1980 m
2. 2000
3. 330 m
4. 350 m

Answer: (1) 1980 m

Question 49. Wave motion transfers

1. Matter
2. Energy
3. Momentum
4. All of these

Answer: (2) Energy

Question 50. The distance between two successive compressions is

1. λ/2
2. λ/4
3. λ
4. 2 λ
5. Answer: (3) λ

Question 51. Sound waves can travel

1. Only in solid
2. Only in liquid
3. Only in gas
4. In all (Solid, Liquid, gas)

Answer: (4) In all (Solid, Liquid, gas)

Question 52. The speed of sound in air

1. Decreases with increase in temperature
2. Remains the same with an increase in temperature
3. Remains the same with a decrease in temperature
4. Increases with increase in temperature

Answer: (1) Decreases with an increase in temperature

Question 53. Sound wave is

1. Transverse
2. Longitudinal
3. Both transverse and longitudinal
4. None of these

Answer: (2) Longitudinal in nature

Question 54. The distance between a compression and the adjoining rarefaction is

1. λ/4
2. λ/2
3. (3) λ
4. 2λ

Answer: (2) λ/2

Question 55. Which of the following waves is a mechanical wave?

1. Lightwave
2. Sound wave
3. X-rays
4. Ultra-violet ray

Answer: (2) Sound wave

Question 56. The speed of sound is maximum in

1. Air
2. Hydrogen
3. Water
4. Iron

Answer: (4) Iron

Question 57. In SONAR, we use

1. Infrasonic
2. Radiowaves
3. Audible sound
4. Ultrasonic

Answer: (4) Ultrasonic

Question 58. Infrasound can be heard by

1. Bat
2. Rhinoceros
3. Dolphins
4. Human beings

Answer:(2) Rhinoceros

Atomic Structure MCQs

Question 1. The smallest part of an element that retains the chemical properties of the element is

1. Electron
2. Molecule
3. Atom
4. Proton

Answer: (4) Proton

Question 2. Electron was discovered by

1. William Crookes
2. A. Arrhenius
3. Michael Faraday
4. J. J. Thomson

Answer: (4) J. J. Thomson

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. Cathode rays are composed of

1.  Radiation
2. Thermal radiation
3.  Beam of negatively charged particles
4.  Positively charged particles

Answer: (3) Beam of negatively charged particles

WBBSE Class 9 atomic structure MCQs with answers

Question 4. Cathode rays are deflected under the influence of electromagnetic fields because cathode rays are

1.  Electromagnetic radiation (EMR, i-e., light)
2. Positively charged particles
3. Beam of neutral particles
4. Beam of electrons

Answer: (4) Beam of electrons

Question 5. In a perforated cathode ray tube, other rays other than cathode rays were found. These rays are

1. Protons
2. Electrons
3. Radiation
4. Neutrons

Answer: (3) Radiation

Question 6. Who among the following got Nobel Prize twice?

1. Rutherford
2. Bohr
3. Einstein
4. Marie Curie

Answer: (4) Marie Curie

Question 7. Radioactivity was discovered by

1. Rutherford
2. Becquerel
3. Marie Curie
4. Pierre Curie

Answer: (3) Marie Curie

Atomic structure multiple choice questions for WBBSE Class 9

Question 8. Radioactivity was first recognised while working with which element?

1. Uranium
2. Thorium
3. Polonium
4.  Barium

Answer: (1) Uranium

Question 9. The concept of nucleus of an atom was given by

1. J. J. Thomson
2. Neils Bohr
3.  Rutherford
4. M. Curie

Answer: (3) Rutherford

Question 10. The diameter of the nucleus is of the order of

1. 10^–3cm
2. 10^–23cm
3. 10^–3 cm
4. 10^–13 cm

Answer: (4) 10^–13 cm

Question 11. From the fact that a helium atom is four times as heavy as a. hydrogen atom, Rutherford predicted the existence of

1. Proton
2. Isotope
3. Neutron
4. Nucleus

Answer: (1) Proton

Important atomic structure questions for Class 9 Physical Science

Question 12. From the study of sun spectra, the element first identified is

1.  Helium
2. Hydrogen
3. Uranium
4. Gold

Answer: (1) Helium

Question 13. Which of the following concepts is not connected to Bohr’s model?

1. Circular shell or orbit
2. Quantization
3.  Line spectra of hydrogen
4. Nuclear force

Answer: (2) Quantization

Question 14. An electron in a Bohr’s orbit is associated with definite

1. Radius
2. Velocity
3. Energy
4. All of the above

Answer: (3) Energy

Question 15. lonization energy of hydrogen atom, as calculated (by Bohr) and experimentally obtained, is

1. 13.56 eV
2. 13.56 J
3. 13.56 Cal
4. None of these

Answer: (1) 13.56 eV

WBBSE Class 9 Physical Science MCQs on atom models

Question 16. Which of the following is considered as a limitation of Bohr’s model? It wa unable to explain

1. E_{n ,} ie., energy of the nth shell electron of hydrogen
2. Ionization energy of hydrogen
3.  Line spectrum of helium
4. Line spectrum of hydrogen

Answer: (2) lonization energy of hydrogen

Question 17. On which of the following, Rutherford’s model differs from Bohr’s model?

1. Circular shape of orbit
2. Concept of the nucleus
3. Empty space in an atom
4. Stability of an atom

Answer: (4) Stability of an atom

Question 18. Which of the following is true?
(A = mass number, Z = atomic number, N = number of neutrons)

1. A= Z
2. A=Z-N
3. A=Z+N
4.  A=N-Z

Answer: (3) A=Z+N

Question 19. Isotopes of an element have the same

1. Mass number (A)
2. Number of neutrons
3. Number of protons
4. Number of protons but not electrons

Answer: (3) Number of protons

Solved MCQs on atomic structure for WBBSE Class 9

Question 20. Isotopes are atoms with same number of

1. Neutrons
2. Protons
3. Electrons
4. Protons

Answer: (1) Neutrons

Question 21. Isobars are atoms having same number of

1. Protons
2. Nettvons
3. Electrons
4. Protons + Neutrons

Answer: (4) Protons + Neutrons

Question 22. Mass of a ¹²C isotope, in AMU unit is,

1.  4
2. 12
3. 1/12
4. None of them

Answer: (2) 12

Question 23. The ground state electron configuration of potassium (Z = 19) is

1. 2, 8, 8, 1
2. 2, 8, 9,0
3.  2, 9, 8, 0
4. 2,7, 8, 2

Answer: (1) 2, 8, 8, 1

Question 24: Atoms of which element have no neutron?

1. Oxygen
2. Hydrogen
3. Carbon
4. Nitrogen

Answer: (2) Hydrogen

Bohr’s model and Rutherford’s model MCQs Class 9 WBBSE

Question 25. Which force binds the nucleons?

1. Gravitational force
2. Electrostatic force
3. Nuclear force
4.  None of these

Answer: (3) Nuclear force

Question 26. Which scientist first enunciated the atomic concept of matter?

1. Newton
2.  Einstein
3. Dalton
4. None of these

Answer: (3) Dalton

Question 27. The atomic number is

1. Mass of an atom x
2. Total number of protons and neutrons
3. Number of protons
4. Number of neutrons

Answer: (3) Number of protons

Question 28. The maximum possible number of electrons in the outermost shell of an atom is

1. 16
2. 18
3.  8
4. 10

Answer: (3) 8

29. The magnitude of the negative charge an electron carries is

1. 1.602 x 10^–2 coulombs
2. 0.602 x 10 ^–9 coulombs
3. 1.602 x 10^–19 coulombs
4.  1.602 x 10^–25 coulombs

Answer: (3) 1.602 x 10^–19 coulombs

Question 30. If two isotopes of a certain element are known, it follows: that the atoms of the element

1. Differ chemically frorn each other
2. Have different numbers of electrons surrounding their nucle.
3. Have different numbers of neutrons in their nuclei.
4.  Have the same mass number.

Answer: (3) Have different numbers of neutrons in their nuclei.

Best multiple-choice questions on atomic structure for WBBSE Class 9

Question 31. Which of the following are examples of isotopes

1. ¹⁴C and , ¹⁴N
2. ⁴⁰K and, ⁴⁰Ca
3. ₈ ¹⁶O and ₈ ¹⁸O
4. None of these

Answer: (3) ₈ ¹⁶O and, ₈ ¹⁸O

Question 32. Sodium atom forms a cation by losing one electron. The cation will be 

1. S⁺
   
2. Na⁺
3.  Kt⁺
4. None of these

Answer: (2) Na⁺

Question 33. A deuteron contains

1. A neutron and position
2. A neutron and a proton
3. A neutron and two protons
4. A proton and two neutrons

Answer: (2) A neutron and a proton

Question 34. The nucleus of an atom contains

1. Electrons
2. Protons alone
3. Neutrons alone
4. Protons and neutrons

Answer: (4) Protons and neutrons

Question 35. The neutron was discovered by

1. J .J. Thomson
2.  G. T. Seaborg
3. E. Rutherford
4. James Chadwick

Answer: (4) James Chadwick

Question 36. The number of electrons in the nucleus of ₆C¹² is

1. 6
2. 12
3. 0
4. 3

Answer: (3) 0

Question 37. Positron is

1. _{_1} ⁰e
2. ₊₁⁰e
3.   ₁¹H
4.  None of these

Answer: (2)  ₊₁⁰e

WBBSE Class 9 Physical Science subatomic particles MCQs

Question 38. The average distance of an electron in an atom from its nucleus is of the order of 

1. 10⁶m
2. 10^–6m
3. 10^–10m
4. 10^–15m

Answer: (3) 10^–10 m

Question 39. A neutral atom (atomic no. > 1) contains

1.  Proton only
2. Neutron + Proton
3. Neutron + Electron
4. Neutron + Proton + Electron

Answer: (4) Neutron + Proton + Electron

Question 40. The radius of an atom is of the order of

1. 10^–10cm
2. 10^–13cm
3. 10^–15cm
4.  10^–8cm

Answer: (4) 10^–8 cm

Question 41. Chlorine atom differs from chlorine ion in the number of which of the following ?

1. Protons
2. Neutrons
3. Electrons y
4.  Both Protons and Neutrons

Answer: (3) Electrons

Question 42. Neutrons are present inthe nuclei of all elements except

1. Hydrogen
2. Oxygen
3. Deuterium
4. Chlorine

Answer: (1) Hydrogen

Question 43. When electrons revolve in stationary orbits 

1. There is no change in energy level
2. They become stationary
3. They are gaining kinetic energy
4. There is increase in energy

Answer: (1) There is no change in energy level

Question 44. Which of the following isoelectronic species has less electrons than protons?

1. O^2-
   
2.  F^–
3. Na⁺
   
4. Mg²⁺

Answer: (1) O^2-

Question 45. As we move away from the nucleus, the energy of an orbit

1. Decreases
2. Increases
3. Remains unchanged
4. None of these

Answer: (2) Increases

Question 46. By addition of one electron in the outermost shell of a chlorine atom, it produces a

1. New atom
2. Anion
3. Cation
4. No change

Answer: (2) Anion

Question 47. Nucleons are

1. Only protons
2. Only neutrons
3.  Protons and neutrons
4. Protons, electrons and neutrons

Answer: (3) Protons and neutrons

Question 48. Rutherford’s a-particle scattering experiment led to the discovery of

1. Electrons
2. Protons
3. Neutrons
4. Atomic nucleus

Answer: (4) Atomic nucleus

Question 49. The electronic configuration of a sodium atom is

1.  2, 8, 3
2. 2, 8, 8
3.  2, 8, 1
4. 2,5, 3

Answer: (3) 2, 8, 1

Question 50. The valency of the element having electronic configuration 2, 8, 8, 1 is

1. 1
2. 2
3.  3a
4. 7

Answer: (1) 1

 

Concept Of Mole MCQs

Question 1. 1 mole is the number of atoms in exactly

1. 1g of  ¹²C
2. 12 g of ¹²C
3. 1/12 g of ¹²C
4. None of these

Answer: (2) 12 g of ¹²C

Question 2. The mass of a C^-12 atom is

1. 12g
2. 1/12 g
3. 12/ N_A g
4. 12 × N_A g 

Answer: (3)  12/ N_A g

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. The number of moles (n), the number of particles (N) and the Avogadro number (N_A) are related as

1. n =N_A/N
2. N/N_A=N
3. n = N/N_A
4.  n = N.N_A

Answer: (3) n = N/N_A

Question 4. 16 g of oxygen is the mass of oxygen of

1. One oxygen atom
2. One oxygen molecule
3. 1-mole oxygen molecule
4. One-mole oxygen atom

Answer: (4) One-mole oxygen atom

WBBSE Class 9 concept of mole MCQs with answers

Question 5. 6.4 g of oxygen is equivalent to

1. 0.4 mol of oxygen atoms
2. 0.4 mol of oxygen molecules.
3. 0.2 mol of oxygen atoms
4. None of these

Answer. (1) 0.4 mol of oxygen atoms

Question 6. 0.10 mol of carbon is equivalent to

1.  1.2 g of carbon
2. 1/12 g of carbon
3. 12.0 g of carbon
4. 0.1 g of carbon

Answer:(1) 1.2 g of carbon

Question 7. A sample is known to contain 2 x 6.022 x 10²³. hydrogen atoms. How many mol hydrogen atoms does it contain?

1. 1 mol
2. 1/2 mol
3. 2 mol
4. N_A mol

Answer: (3) 2 mol

Question 8. Formula mass of water (H₂O) is

1. 33
2. 17
3.  10
4. 18

Answer: (4) 18

Concept of mole multiple choice questions for WBBSE Class 9

Question 9. Consider two gases A and B or ideal gas with M_A > M_B. The molar volumes (Vm) at given pressure and temperature are like

1. V_m(A)= V_m(B)
2. V_m(A)> V_m(B)
3. V_m(A) <V_m(B)
4. No relation

Answer: (1) V_m(A)= V_m(B)

Question 10.A sample contains m g of a compound X (mx = molar mass). The sample contains n mol of X. Then n, m and M are related as

1. M=m.n
2. M= n/n
3. M= n/m
4.  n=m.M

Answer: (2) M = m/n

Question 11. ‘Mole’ means

1. A molecule
2. Number of molecules
3. Number of atoms
4. Avogadro’s number of any particle

Answer: (4) Avogadro’s number of any particle

Question 12. 0.012 kg of C^-12isotope contains how many C^-12atoms ?

1. 12
2. 6.022 x10²³
   
3. 1.66 x10^-24 g
4. 12 g atom .

Answer: (2) 6.022 x10²³

Important mole concept questions for Class 9 Physical Science

Question 13. Avogadro’s number is used in

1. Chemistry only
2.  Physics only
3. Biology only
4. Chemistry, physics and biology

Answer: (4) Chemistry, physics and biology

Question 14. Unit of relative atomic mass is

1. Gram
2. Kilogram
3. a.m.u.
4. No unit

Answer: (4) No unit

Question 15. Which scientist first gave the concept of molecule?

1.  Dalton
2. Avogadro
3. Berzilius
4. Boyle

Answer: (2) Avogadro

WBBSE Class 9 Physical Science MCQs on mole and molar mass

Question 16. What is the volume of 1 gram-molecule of a gas or vapour at NTP?

1. 22.4 ml
2. 22.4 lit
3.  1000 ml
4. 2.24 lit

Answer: (2) 22.4 lit

Question 17. In the reaction, N₂+3H₂=2NH₃ the ratio of volumes of nitrogen, hydrogen, and ammonia is 1 : 3: 2. These figures illustrate the law of

1. Constant proportion
2. Multiple proportion
3. Reciprocal proportion
4.  Gay Lussac’s law of gaseous volumes

Answer: (4) Gay Lussac’s law of gaseous volumes

Question 18. At NTP, 5.6 lit of a gas weighs 8 grams. The vapour density of the gas is 

1.  32
2. 40
3. 16
4. 8

Answer: (3) 16

Solved MCQs on mole concept for WBBSE Class 9

Question 19. Which of the following contains the least number of molecules?

1. 19 H₂
2. 2g N₂
3. 4g O₂
4.  11g CO₂

Answer: (2) 2g N₂

Question 20. Which of ‘the following volumes of the gas at NTP contains the largest number of molecules?

1. 200 ml H₂
2.  100 ml O₂
3. 150 ml N₂
4. 22.5 ml NH₃

Answer: (1) 200 ml H₂,

Question 21. Which one of the following statements is not applicable to 1 mole of carbon dioxide?

1. 22 g CO₂
2. 22.4 lit of the gas
3. 1 gram atom of carbon and 2 gram atoms of oxygen
4. 6.023 x 10²³ molecules of carbon dioxide

Answer: (1) 22 g CO₂

Mole-mass and mole-volume relationship MCQs Class 9 WBBSE

Question 22. A mole of any gas 

1. Always occupies one liter
2. Always occupies 22.4 lit at NTP
3. Can occupy any volume at NTP
4. Always occupies 11.2 lit at NTP

Answer: (2) Always occupies 22.4 lit at NTP

Question 23. The latest standard of atomic weight is 

1. Hydrogen = 1
2. Oxygen = 16
3. Carbon = 12
4. Nitrogen = 14

Answer: (3) Carbon = 12

Question 24. The approximate number of molecules in 4.25 g of ammonia is 

1. 1.0 x 10²³
2. 1.5 x 10²³
3. 2.0 x 10²³
4. 3.5 x 10²³

Answer: (2) 1.5 x 10²³

Best multiple choice questions on mole concept for WBBSE Class 9

Question 25. Atomic weight of chlorine is 35.5. It has two isotopes of atomic weights 35 and 37. What is the percentage of the heavier isotope in the sample?

1. 5
2. 25
3. 20
4. 15

Answer: (2) 25

Question 26 Number of molecules in one litre of water is close to 

1. \(\frac{6.023}{23.4} \times 10^{23}\)
2. 18 x 6.023 x 10²³
3. \(\frac{18}{22.4} \times 10^{23}\)
4. 55.5 x 6.023 x 10²³

Answer: (4) 55.5 x 6.023 x 10²³

Question 27. Volume at NTP of 0.22 g of CO₂ is the same as that of 

1. 0.01 g of H₂
2. 0.085 g of NH₃
3. 320 mg of gaseous SO₂
4. All of the above

Answer: (4) All of the above

Question 28. Avogadro’s number of helium atoms weighs 

1. 1 g
2. 4 g
3. 8 g
4. 4 x 6.025 x10²³ g

Answer: (2) 4 g

Question 29. The molecular mass of CO₂ is 44 a.m.u. Biotec? s number is 6.023 x 10²³, therefore, the mass of one molecule of CO₂ , is

1.  7.31 x 10^-23
2. 3.65 x 10^-23
3. 1.01 x 10^-23
4. 2.01 x 10^-23

Answer: (1) 7.31 x 10^-23

Question 30. 4.0 grams of caustic soda contain 

1. 6.023 x 10²³ atoms of hydrogen
2. 4 g atoms of sodium
3. 6.023 x 10²²atoms of sodium
4. 4 moles of caustic soda

Answer: (3) 6.023 x 10²² atoms of sodium:

WBBSE Class 9 Physical Science Avogadro’s number MCQs

Question 31. Which of the following weighs the least?

1. 24 g of magnesium
2. 0.9 moles of nitric oxide
3. 22.4 lit of N₂
4. 6.023 x 10²⁴ molecules of oxygen

Answer: (1) 24 g of magnesium

Question 32. One mole of CO₂ contains

1. 6.023 x 10²³ atoms of carbon
2. 6.023 x 10²³ atoms of oxygen
3. 18.1 x 10²³ molecules of carbon dioxide
4. 3 gram atoms of carbon dioxide

Answer: (1) 6.023 x 10²³  atoms of carbon

Question 33. One a.m.u. is

1. 1.00748 g
2. 0.000549 g
3. 1.66 x.10^-24 g
4. 6.023 x 10^-23 g

Answer:  (3) 1.66 x 10^-24g

Question 34. The vapour density of a gas is 11.2. The volume occupied by 11.2 g of the gas at NTP is

1. 1 L
2. 11.2 L
3. 22.4 L
4. 10 L

Answer: (2) 11.2 L

Question 35. The vapour density of pure ozone would be 

1. 16
2. 24
3. 32
4. 48

Answer: (2) 24

Question 36. At STP 5.6 lit of a gas weights 60 g. The vapour density of the gas is.

1. 30
2. 60
3. 120
4. 240

Answer: (3) 120

Question 37. The largest number of molecules is in 

1.  34 g water
2. 54 g of CO₂
3. 46 g of CH₃OH
4. 54 g of N₂ O₅

Answer : (1) 34 g water

Question 38. The number of oxygen atoms in 4.4 g of CO, is approximately 

1. 1.2 x 10²³
2. 6 x 10²³
3. 6 x10²²
4. 12 x 10²³

Answer:  (1) 1.2 x 10

Question 39. The number of molecules in 16 g of methane (CH,) is 

1. 3.0 x 10²³
2. 6.023 x 10²³
3. \(\frac{16}{6.023} \times 10^{23}\)
4. \(\frac{16}{3} \times 10^{23}\)

Answer. (2) 6.023 x 10²³

Question 40. If 0.56 g of a gas occupies 280 ml at NTP, then its molecular mass is 

1. 4.8
2.  44.8
3. 2
4. 22.4

Answer: (2) 44.8

 

Solution MCQs

Multiple Choice Type :

Question 1. The ratio of the components of a solution is

1. Fixed
2. May vary
3. May vary to any extent
4. May vary within a limit

Answer: (4) May vary within a limit

Question 2. Aerated cold drinks contain CO₂, sugar, and water. Her solution is of

1. Sugar
2. CO₂
3. Water
4. Sugar and CO₂

Answer: (4) Sugar and CO₂ etc

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. Which one is the true solution?

1. Solution of common salt
2. Solution of chalk
3. Milk
4. Butter

Answer: (1) Solution of common salt

Question 4. The particle size of a colloid is

1. 10^-8cm
2. 10^-4 cm
3. 10^-3cm
4. 10^-5 cm−10^-7

Answer: (4) 10^-5 cm−10^-7

WBBSE Class 9 solutions MCQs with answers

Question 5. Which one of the following will not diffuse?

1. Suspension
2. True solution
3. Colloids
4. None

Answer: (1) Suspension

Question 6. When liquid is dispersed in a solid, the production is called

1. Gel
2. Sol
3. Emulsion
4. Foam

Answer: (1) Gel

Question 7. Which of the following in an aqueous solution can enter into the intermolecular space of water?

1. Urea
2. Protein
3. DNA
4. Starch

Answer: (1) Urea

Solutions multiple choice questions for WBBSE Class 9

Question 8. Solubility of which one of the following increases with an increase in temperature 7

1. O₂
2. NH₃
3. KNO₃
4. SO₂

Answer: (3) KNO₃

Question 9. Which one of the following solutions is unstable?

1. Saturated
2. Unsaturated
3. Supersaturated
4. Colloidal

Answer: (3) Supersaturated

Question 10. Which one of the following solvents is used to remove nail polish?

1. Ethyl  alcohol
2. Methyl alcohol
3. Acetone
4. Turpentine oil

Answer: (3) Acetone

Question 11. Solution is a

1. Mixture
2. Element
3. Compound
4.  None of these

Answer: (1) Mixture

Important solution chapter questions for Class 9 Physical Science

Question 12. The solvent of sulphur is

1. Water
2. Ethyl alcohol
3. Carbon disulphide
4. Benzene

Answer: (3) Carbon disulphide

Question 13. If a saturated solution is heated

1. Solution becomes unsaturated
2.  Solution becomes super saturated
3. Solution remains saturated
4. All of the above

Answer: (2) Solution becomes super saturated

Question 14. If more solvent is added to a saturated solution 

1. Solution becomes super saturated
2.  Solution becomes unsaturated
3.  Solution remains saturated
4. All of the above

Answer: (2) Solution becomes unsaturated

Question 15. The solubility of which substance decreases with an increase in temperature?

1. KNO₃
2.  CaSO₄
3. NaCl
4. None of these

Answer: (2) CaSO₄

WBBSE Class 9 Physical Science MCQs on types of solutions

Question 16. When temperature rises, the solubility of gas in liquid 

1. Decreases
2.  Increases
3. Unaltered
4. None of these

Answer: (1) Decreases

Question 17. If the size of the particles is between 10^-5 cm to 10^-7 cm then the solution will be 

1. True solution
2.  Suspension
3. Colloid
4. None of these

Answer: (3) Colloid

Question 18. The number of water molecules present in washing soda is 

1.  5
2.  6
3. 10
4.  7

Answer: (3) 10

Question 19. A deliquescent substance is

1.  Magnesium chloride
2. Washing soda
3. Glauber’s salt
4. Blue vitriol

Answer: (1) Magnesium chloride

Question 20. Fog is

1.  A solution of liquid in gas
2. A solution of gas in gas
3. A solution of solid in gas
4. A solution of liquid in liquid

Answer: (1) A solution of liquid in gas

Solved MCQs on solutions for WBBSE Class 9

Question 21. Smoke is

1. A solution of gas in gas
2. A solution of carbon in gas
3. A solution of liquid in liquid
4. A solution of solid in solid

Answer: (4) A solution of carbon in gas

Question 22. Solubility is almost unchanged with rise in temperature in case of 

1. NaCl
2. CaSO₄
3. NaSO₄  , 10 H2O
4.  KNO₃

Answer: (1) NaCl

Question 23. Phosphorus pentoxide is a

1. Efflorescent substance
2. Deliquescent Substance
3.  Drying agent
4. None of these

Answer: (3) Drying agent

Question 24. Is soluble in chloroform.

1. Sugar
2. Common salt
3. Oil
4. Blue vitriol

Answer: (3) Oil

Question 25. lodine is soluble in

1. Water
2.  Alcohol
3.  Acetone
4. None of these

Answer: (2) Alcohol

Concentration of solutions MCQs Class 9 WBBSE

Question 26. The unit of concentration of the solution is 

1. g/L
2. g/m²
   
3. g/m
4. g/cm

Answer: (1) g/L

Question 27. If an excess amount of solute is dissolved in a saturated solution then the solution is Called

1. Unsaturated solution
2.  Supersaturated solution
3. Colloid
4. Emulsion

Answer: (2) Supersaturated solution

Question 28. A solution is 

1. Solvent dissolved in solute
2.  A heterogeneous mixture
3.  A homogeneous mixture
4. Only a liquid in liquid

Answer: (3) A homogeneous mixture

Question 29. Depending on “which phase dissolved in which phase”, how many types of solutions do we consider?

1. 1
2. 3
3. 6
4. 9

Answer: (3) 6

Question 30. A true solution has the feature

1. Particle size less than 1 mm
2. Separation by filtration
3.  Solute particles are large groups of particles
4. Separation by a semipermeable membrane

Answer: (1) Particle size less than 1 mm

Best multiple choice questions on solutions for WBBSE Class 9

Question 31. A colloidal solution is associated with the feature

1. Solute particles are large groups of insoluble particles
2. Particle size is 1 to 100 nm
3. Separation by filtration
4. None of these

Answer: (2) Particle size is 1 to 100 nm

Question 32. A suspension is associated with the feature

1. Solutes are atoms or ions
2. Particle size is 1 to 100 nm
3. Particle size is less than 100 nm
4. Separation by filtration

Answer: (4) Separation by filtration

Question 33. Mist or fog are examples of a colloid where A is dispersed in B. A and B are

1. Gas-liquid
2. Liquid – gas
3. liquid-liquid
4. Solid-liquid

Answer: (2) liquid – gas

Question 34. Which of the following is not a colloidal solution?

1.  Icecream
2. Milk
3. Smoke
4. NaCl in water

Answer: (4) NaCl in water

Question 35. Which of the following is not a technical name for colloids?

1. Foam
2. Sol
3. Gel
4. Olium

Answer: (4) Olium

Question 36. An alloy is a colloid having dispersed and medium as

1. Liquid in solid
2. Solid in liquid
3. Liquid in liquid
4. Solid in solid

Answer: (4) Solid in solid

WBBSE Class 9 Physical Science solubility and saturation MCQs

Question 37. Soap or detergent is an example of

1. Emulsifier
2. Sol
3. Aerosol
4. Solid foam

Answer: (1) Emulsifier

 

Water MCQs

Question 1. The mass ratio of hydrogen and oxygen in water is

1. 2:1
2. 1:2
3. 1:8
4. 8:1

Answer: (3) 1:8

Question 2. Who first recognised that water is a compound of two elements (hydrogen and oxygen) in 1783?

1. Lavoisier
2. Cavendish
3. J. Thomson
4. Robert Boyle

Answer: (1) Lavoisier

Question 3. What is the fundamental property that makes water so important?

1. Density
2. Its crystal structure
3.  Its boiling point
4.  Hydrogen bonds

Answer: (1) Density

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 4. In pressure cooker, water boils at T°C; T is

1. 100°C os
2. 100°C
3. < 100°C
4. None of these

Answer: (2) > 100°C

WBBSE Class 9 water chapter MCQs with answers

Question 5. At 3.98°C (nearly 4°C), water has a special property. What is this?

1. Density is minimum
2. Volume is maximum
3. Density is maximum
4. None of these

Answer: (3) Density is maximum

Question 6. Water can act as

1. An. acid only
2. A base only
3. Both as acid and a base
4. Neither acid nor base

Answer: (3) Both as acid and a base

Question 7. ppm is a unit sometimes used to express concentration level of pollutants in water. This ppm is equivalent to

1. g/l
2. ml/l
3. Kg/ml
4.  mg/\(\mathrm{dm}^3\)

Answer: (2) ml/l

Water multiple choice questions for WBBSE Class 9

Question 8. Hard water contains appreciable amount of concentration of which ions ?

1. \(\mathrm{Cl}^{-}\) and \(\mathrm{NO}^{-}\)
2. \(\mathrm{Na}^{+}\) and \(\mathrm{K}^{+}\)
3. \(\mathrm{CO}^{-2}\) and \(\mathrm{Cl}^{-}\)
4. \(\mathrm{Ca}^{+2}\) \(\mathrm{Fe}^{+2}\) and \(\mathrm{Mg}^{+2}\)

Answer: (4) \(\mathrm{Ca}^{+2}\) \(\mathrm{Fe}^{+2}\) and \(\mathrm{Mg}^{+2}\)

Question 9. Temporary hardness is due to the presence of which compound in water?

1. NaCl
2. \(\mathrm{CaSO}_4\)
3. \(\mathrm{NaNO}_3\)
4.  \(\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2\)

Answer: (4) \(\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2\)

Question 10. Which state of water provides the medium of life?

1. Solid
2. Liquid
3.  Vapour
4. Vapour at 100°C.

Answer: (2) Liquid

Important water chapter questions for Class 9 Physical Science

Question 11. Which property of water controls environmental temperature?

1. Specific heat capcity
2. Latenet heat of vaporisation
3. Density
4. Surface tension.

Answer: (1) Specific heat capcity

Question 12. Air obtained from dissolved air in water contains oxygen and nitrogen respectively in the percentage

1. 21% \(\mathrm{O}_2\), 78%  \(\mathrm{N}_2\)
2. 17% \(\mathrm{O}_2\), 83%  \(\mathrm{N}_2\)
3. 33%\(\mathrm{O}_2\), 66% \(\mathrm{N}_2\)
4. 66% \(\mathrm{O}_2\), 33%  \(\mathrm{N}_2\)

Answer: (3) 33% \(\mathrm{O}_2\)  66% \(\mathrm{N}_2\)

Question 13. What are the prescribed limits of pH of potable water?

1.  4.5.
2. 6.5-4.5
3. 1.5-4.5
4. 8.5-9.5

Answer: (2) 6.5-4.5

Question 14. Which of the following ions is responsible for the hardness of water?

1.  \(\mathrm{Fe}^{+2}\)
2. \(\mathrm{Na}^{+}\)
3. \(\mathrm{HCO}_3^{-}\)
4. \(\mathrm{SO}_4^{2-}\)

Answer: (1)  \(\mathrm{Fe}^{+2}\)

WBBSE Class 9 Physical Science MCQs on properties of water

Question 15. The salt which is the cause of the hardness of water is 

1.  \(\mathrm{NH}_4 \mathrm{Cl}\)
2. \(\mathrm{NaNO}_3\)
3. \(\mathrm{MgSO}_4\)
4. \(\mathrm{K}^{2}{SO}_4\)

Answer: (3) \(\mathrm{MgSO}_4\)

Question 16. Soap is a salt of

1. Acetic acid
2.  Palmitic acid
3. Formic acid
4. Nitric acid

Answer: (2) Palmitic acid

Question 17. Which of the following metals does not react with cold and hot water?

1. Fe
2. K
3.  Ni
4. Ag

Answer: (4) Ag

Solved MCQs on water for WBBSE Class 9

Question 18. Which of the following is soft water?

1. Rainwater
2. River water
3. Tubewell
4.  Seawater

Answer: (1) Rainwater

Question 19. Which of the following metals reacts easily with water at ordinary temperature?

1. Ca
2. Zn
3. Cu
4. Ag

Answer: (1) Ca

Question 20. Tubewell water becomes brown due to

1. \(\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2\)
2.  \(\mathrm{Fe}\left(\mathrm{HCO}_3\right)_2\)
3.  \(\mathrm{MgSO}_4\)
4. \(\mathrm{MgCl}_2\)

Answer: (2) \(\mathrm{Fe}\left(\mathrm{HCO}_3\right)_2\)

Water cycle and its importance MCQs Class 9 WBBSE

Question 21. D₂O reacts with CaC₂ to form

1. \(C_2 D_2\)
2. \({Ca} D_2\)
3. \(\mathrm{Ca}_2 \mathrm{D}_2 \mathrm{O}\)
4. \(\mathrm{CD}_2\)

Answer: (1) \(C_2 D_2\)

Question 22. Permutit is regenerated by passing

1. 10% NaOH solution
2. 10% \(\mathrm{NH}_4 \mathrm{Cl}\) solution
3. 10% NaCl solution
4. None of these

Answer: (3) 10% NaCl solution

Best multiple choice questions on water for WBBSE Class 9

Question 23. If 1 lit. water contains 0.001 mol \(\mathrm{MgSO}_4\)what will be the hardness of water ?

1. 100 ppm
2. 200 ppm
3. 500 ppm
4. 150 ppm

Answer: (3) 500 ppm

Question 24. Water has high boiling point because

1. Specific heat of water is high
2. Heat of dissociation is high
3. Presence of hydrogen bonding
4. Molecule weight is low

Answer: (3) Presence of hydrogen bonding

Question 25. Anion exhange resin is regenerated by passing

1. Dilute NaCl solution
2. Dilute H₂SO4 solution
3. Dilute HNO3 solution
4. Dilute NaOH solution

Answer: (4) Dilute NaOH solution

Question 26. When hard water is passed through zeolite, the Na* (present in zeolite) is exchanged by

1. \(\mathrm{OH}^{-}\)
2. \(\mathrm{Ca}^{+2}\)
3. \(\mathrm{SO}^{-2}\)
4. \(\mathrm{H}^{+}\)

Answer: (2) \(\mathrm{Ca}^{+2}\)

Question 27. Water is oxidised to oxygen by

1. \(\mathrm{ClO}_2\)
2. \(\mathrm{KMnO}_4\)
3.  \(\mathrm{H}_2 {O}_2\)
4.  \(\mathrm{F}_2\)

Answer: (4) \(\mathrm{F}_2\)

WBBSE Class 9 Physical Science hard and soft water MCQs

Question 28. Sodium promptly reacts with water at ordinary temperature to form sodium hydroxide and what?

1.  Oxygen
2. Nitrogen
3.  Chlorine
4. Hydrogen

Answer: (4) Hydrogen 3