Here we are providing Class 9 Science Objective Chapter – 11 Work, Power and Energy because its very important for Class 9 students as we all know that every board exam question has MCQs so that students should practice these questions so that students can get good marks in board. Class 9 Science Objective Chapter – 11 Work, Power and Energy is an extremely important and its also a year in which students learn the fundamentals of concepts that help them lay a solid foundation for their higher education. Here we are providing in Class Class 9 Science Objective Chapter – 11 Work, Power and Energy 100+ questions so that students practice more and more. If you want class wise Notes Then Click Here
Class 9 Science Objective Chapter – 11 Work, Power and Energy
1. Work done by centripetal force is
( A ) > 0
( B ) ≥ 0
( C ) < 0
( D ) 0
Ans – ( D )
2.An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are lo m above the ground, they have the same.
( A ) acceleration
( B ) momenta
( C ) potential energy
( D ) kinetic energy
Ans – ( A )
3.A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car
( A ) does not change
( B ) becomes twice to that of initial
( C ) becomes 4 times that of initial
( D ) becomes 16 times that of initial
Ans – ( A )
4. When a body falls freely towards the earth, then its total energy
( A ) Decreases
( B ) Increases
( C ) First increases and then decreases
( D ) Remains constant
Ans – ( D )
5.In case of negative work the angle between the force and displacement is (NCERT Exemplar)
( A ) 0°
( B ) 45°
( C ) 90°
( D ) 180°
Ans – ( D )
6. If work is done at a faster rate, then
( A ) power is more
( B ) No power is required to do work
( C ) power is less
( D ) Infinite power is required
Ans – ( A )
7.An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are lo m above the ground, they have the same.
( A ) acceleration
( B ) momenta
( C ) potential energy
( D ) kinetic energy
Ans – ( A )
8. Moon revolves around the earth due to gravitational force (F) of earth on moon. The work done by the gravitational force is (r = radius of circular orbit of moon)
( A ) F.2πr
( B ) F.πr
( C ) zero
( D ) negative work
Ans – ( C )
9.An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same
( A ) acceleration
( B ) momenta
( C ) potential energy
( D ) kinetic energy
Ans – ( A )
10.A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²)
( A ) 6 × 10³ J
( B ) 6 J
( C ) 0.6 J
( D ) zero
Ans – ( D )
11. Work done by a body is
( A ) negative, positive or zero
( B ) always positive
( C ) always zero
( D ) always negative
Ans – ( A )
12.A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g =10 m s’2)
( A ) 6×103 J
( B ) 6 J
( C ) 0.6 J
( D ) zero
Ans – ( D )
13.Which one of the following is not the unit of energy?
( A ) joule
( B ) newton metre
( C ) kilowatt
( D ) kilowatt hour
Ans – ( C )
14. 1 W. S = ________?
( A ) 10 joule
( B ) 1 joule
( C ) 3.6 × 106 joule
( D ) 2 joule
Ans – ( B )
15.When a body falls freely towards the earth, then its total energy
( A ) increases
( B ) decreases
( C ) remains constant
( D ) first increases and then decreases
Ans – ( C )
16.The work done on an object does not depend upon the
( A ) displacement
( B ) force applied
( C ) angle between force and displacement
( D ) initial velocity of the object
Ans – ( D )
17. Scientifically, work is said to be done in which of the following cases
( A ) Manish pulls the trolley for a certain distance
( B ) Mira studies for her exam
( C ) Manoj pushes the wall with no change in the position of wall
( D ) Mira pulls the wall with no change in the position of wall
Ans – ( A )
18.A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car
( A ) does not change
( B ) becomes twice to that of initial
( C ) becomes 4 times that of initial
( D ) becomes 16 times that of initial
Ans – ( A )
19.Water stored in a dam possesses
( A ) no energy
( B ) electrical energy
( C ) kinetic energy
( D ) potential energy
Ans – ( D )
20. P.E of a spring increases when it is in the state of
( A ) compression
( B ) neither a nor b
( C ) expansion
( D ) both a and b
Ans – ( D )
21.The number of joules contained in 1 kWh is
( A ) 36 × 105 J
( B ) 3.6 × 107 J
( C ) 36 × 108 J
( D ) 3.7 × 107 J
Ans – ( A )
22. When speed of the moving object is doubled its
( A ) Acceleration is doubled
( B ) Momentum becomes four times more
( C ) K E. is increased to four times
( D ) Potential energy is increased
Ans – ( C )
23.Two army persons A and B each of weight of 500 N climb up a rope through a height of 10 m. A takes 20 s while B takes 40 s to achieve this task. What is ratio of the powers of person A and B?
( A ) 1 : 2
( B ) 1 : 4
( C ) 2 : 1
( D ) 14 : 1
Ans – ( C )
24. A ball is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy when its reaches the maximum height?
( A ) Kinetic energy is double
( B ) Kinetic energy is zero
( C ) Kinetic energy is maximum at maximum height
( D ) Kinetic energy is half of initial value
Ans – ( B )
25.If speed of a car becomes 2 times, its kinetic energy becomes
( A ) 4 times
( B ) 8 times
( C ) 16 times
( D ) 12 times
Ans – ( A )
26. A stone weighing 1 kg is dropped from rest from a height of 4 metres above the ground. When it has free-fallen 1 metre its total energy with respect to the ground is
( A ) 15 J
( B ) 40 J
( C ) 20 J
( D ) 30 J
Ans – ( B )
27.Work done by friction
( A ) increases kinetic energy of body
( B ) decreases kinetic energy of body
( C ) increases potential energy of body
( D ) decreases potential energy of body.
Ans – ( B )
28. The energy possessed by an oscillating pendulum of a clock is
( A ) kinetic energy
( B ) potential energy
( C ) restoring energy
( D ) mechanical energy
Ans – ( D )
29.When a coil spring is compressed, the work is done on the spring. The elastic potential energy
( A ) increases
( B ) decreases
( C ) disappears
( D ) remains unchanged
Ans – ( A )
30. What is the commercial unit of energy?
( A ) electron volt
( B ) W/s
( C ) kW h
( D ) joule
Ans – ( C )
31.One joule work is said to be done when
( A ) a force of 1 N displaces a body by 1 cm
( B ) a force of 1 N displaces a body by 1 m
( C ) a force of 1 dyne displaces a body by 1 m
( D ) a force of 1 dyne displaces a body by 1 cm.
Ans – ( B )
32. Calculate the work done in moving a body of mass 50 Kg through a height of 5 m.(g = 10m/s2)
( A ) 250 J
( B ) 2500 J
( C ) 25 x 103 J
( D ) 2.5 x 105 J
Ans – ( B )
33.SI unit of power is
( A ) watt
( B ) joule
( C ) newton
( D ) metre
Ans – ( A )
34. Find the correct statement
( A ) 1 Gigawatt is equal to 109W
( B ) power is the rate of doing work
( C ) both a and b
( D ) none of these
Ans – ( D )
35.Mechanical energy of a body includes
( A ) kinetic energy only
( B ) potential energy only
( C ) kinetic energy and potential energy
( D ) none of these
Ans – ( C )
36. If a force of F newton moves a body with constant speed v, the power delivered by it is
( A ) F/v
( B ) Fv
( C ) F2v
( D ) v/F
Ans – ( B )
37.Commercial unit of energy is
( A ) joule
( B ) kWh
( C ) watt
( D ) newton
Ans – ( B )
38. According to the law of conservation of energy
( A ) Energy can’t be destroyed
( B ) Energy can’t be created
( C ) Energy can be transformed from one from to another
( D ) All of the above
Ans – ( D )
39.Potential energy of a body depends on its
( A ) position
( B ) configuration
( C ) position and configuration
( D ) mass and velocity
Ans – ( C )
40. In SI system, the unit of P.E. is
( A ) erg
( B ) dyne-cm
( C ) J
( D ) None of these
Ans – ( C )
41.If speed of a car becomes 2 times, its kinetic energy becomes
( A ) 4 times
( B ) 8 times
( C ) 16 times
( D ) 12 times
Ans – ( A )
42. In the SI system, the unit of potential energy is
( A ) newton
( B ) joule
( C ) watt
( D ) metre per second
Ans – ( B )
43. When a body like earth is moving in a circular path the work done in that case is zero because:
( A ) Centripetal force acts in the direction of motion of the body
( B ) Centripetal force acts along the radius of circular path
( C ) Gravitational force acts along the radius of circular path
( D ) Centrifugal force acts perpendicular to the radius of circular path
Ans – ( B )
44. Two bodies of equal weight are kept at heights of h and 1.5 A, respectively. The ratio of their PE is
( A ) 3 : 2
( B ) 2 : 3
( C ) 1 : 1
( D ) 4 : 3
Ans – ( B )
45. A car is accelerated on a leveled road and attains a velocity 4 times of its initial velocity. In this process, the kinetic energy of the car
( A ) Becomes twice to that of the initial
( B ) Becomes four times to that of the initial
( C ) Remains the same
( D ) Becomes 16 times to that of the initial
Ans – ( D )
46. On tripling the speed of motion of a body, the change in K.E. is
( A ) 9 times
( B ) 8 times
( C ) 4 times
( D ) 2 times
Ans – ( A )
47. The type of energy possessed by a simple pendulum, when it is at the mean position is:
( A ) Kinetic energy
( B ) Potential energy
( C ) Kinetic + Potential energy
( D ) Sound energy
Ans – ( A )
48. A stone is tied to a string and whirled in a circular path. The work done by the stone is :
( A ) negative
( B ) zero
( C ) positive
( D ) none of the above
Ans – ( B )
49. A man is carrying the heavy luggage from one platform to the other of a Railway station but still according to the logics of science his work done is said to be zero. Can you opt out the correct reason?
( A ) The force is acting along the direction of displacement of luggage
( B ) The force is acting perpendicular to the direction of displacement of luggage
( C ) The force is acting opposite to the direction of displacement of luggage
( D ) None of these
Ans – ( B )
50. 9800 joule of energy was spent to raise a mass of 50kg, the mass was raised to a height of
( A ) 20m
( B ) 980m
( C ) 10m
( D ) none of these
Ans – ( A )
51. What is the energy possessed by an object due to its motion?
( A ) Potential energy
( B ) Electrical energy
( C ) Kinetic energy
( D ) None of them
Ans – ( C )
52. The linear momentum of a body of mass 2kg is 16kgms−1. What is its K. E?
( A ) 64J
( B ) 70J
( C ) 60J
( D ) none of these
Ans – ( A )
53. The capacity of a body to perform work is called:
( A ) Energy
( B ) Work
( C ) Power
( D ) Heat
Ans – ( A )
54. Potential energy and kinetic energy are types of
( A ) Electrical energy
( B ) Magnetic energy
( C ) Thermal energy
( D ) Mechanical energy
Ans – ( D )
55. The rate of work done is called:
( A ) Energy
( B ) Power
( C ) Capacity
( D ) All of these
Ans – ( B )
56. A body of mass 5 kg is moving with an acceleration of 5 ms-2 gets a displacement of 2m, the work done by the force is:
( A ) 75 J
( B ) 25 J
( C ) 100 J
( D ) 50 J
Ans – ( D )
57. The capacity to perform work is obtained from :
( A ) Food
( B ) Energy
( C ) Power
( D ) All of these
Ans – ( B )
58. Work done is said to be positive when a force causes displacement:
( A ) In its own direction
( B ) In the direction opposite to the applied force
( C ) In the direction at right angles to the direction of applied force
( D ) None of the above
Ans – ( A )
59. Which of the following does not possess the ability to do work not because of motion ?
( A ) a sparrow flying in the sky
( B ) a sparrow moving slowly on the ground
( C ) a sparrow in the nest on a tree
( D ) a squirrel going up a tree
Ans – ( C )
60. Two masses m and 2m are dropped from certain height ‘h’. Then on reaching the ground,
( A ) K.E. of them will be equal
( B ) K.E. of the heavier is 4 times the K.E. of the lighter
( C ) K.E. of the lighter is 4 times the K.E. of the heavier
( D ) K.E. of the heavier is more than that of the lighter
Ans – ( D )
61. The momentum of a bullet of mass 20 g fired from a gun is 10 kg m/s. The kinetic energy of this bullet in kJ will be:
( A ) 25
( B ) 2.5
( C ) 0.25
( D ) 5
Ans – ( B )
62. A rocket rises up in the air due to the force generated by the fuel. The work done by the:
( A ) fuel is negative work and that of force of gravity is positive work
( B ) fuel is positive work and that of force of gravity is negative work
( C ) both fuel and force of gravity do positive work
( D ) both fuel and force of gravity do negative work
Ans – ( B )
63. If a man hold an object of mass 20 kg at 1.3 m then the value of work done will be
( A ) 26 J
( B ) 30 J
( C ) 20 J
Ans – ( D )
64. A body is moved through a distance of 3 m in the following different ways. In which case is the maximum work done?
( A ) when pushed over an inclined plane
( B ) when lifted vertically upward
( C ) when pushed over smooth rollers
( D ) when pushed on a plain horizontal surface
Ans – ( B )
65. Which of the following is a source of energy?
( A ) Sun
( B ) Nuclear reactions
( C ) Tides
( D ) All of the above
Ans – ( D )
