Work and Energy Test

Question 1

1 / -0

Use the following information to answer the next question.

The following table lists the power ratings of different appliances used by a family and the daily operating time of each appliance.
Device	Power rating (W)	Time of operation (h)
Bulb	40	10
Fan	50	9
TV set	120	6
Electric iron	750	1

How many units of energy are consumed by these devices in the month of July?

67.31 units

69.49 units

71.92 units

73.24 units

Question 2

1 / -0

Use the following information to answer the next question.

Three essential criteria for something to qualify scientifically as work done:

I A force must act on a body.

II The body must be displaced.

III Directions of the applied force and the displacement must be the same.

With reference to the scientific definition of work done,

only II is inessential

only III is inessential

both I and II are inessential

both I and III are inessential

Question 3

1 / -0

Use the following information to answer the next question.

Three statements regarding work done:

I A person reading a book is not doing any work as per the scientific definition of work.

II The amount of work done can be expressed in Nm (Newton metre).

III Work done can be positive or negative.

With reference to work done,

only II is true

only III is false

all three statements are true

all three statements are false

Question 4
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A force of 2.4 N is acting on an object, causing the object to be displaced by 1.6 metres in the direction of the force. What is the work done by the force?

A
1.23 J

B
2.56 J

C
3.84 J

D
6.14 J

Question 5
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Scientifically, work is done when a person

A
reads a book for a long time

B
climbs a staircase slowly

C
stands with a heavy load

D
pushes a huge rock

Question 6

1 / -0

Use the following information to answer the next question.

Hydroelectricity is generated by storing a large amount of water at a height and then allowing this water to run over some rotating turbines. These turbines eventually generate electricity.

Which of the following conservation principles is used in a hydropower plant?

Conservation of mass

Conservation of charge

Conservation of energy

Conservation of momentum

Question 7
1 / -0

A car of mass 1200 kg starts from rest and acquires a uniform velocity of 18 m/s. What is the work done on the car?

A
184400 J

B
188400 J

C
194400 J

D
198400 J

Question 8

1 / -0

Use the following information to answer the next question.

Puneet constructs a portable power plant, similar to those used in hydropower plants.

As he opens the tap, the running water rotates the blades of the turbine, as shown in the figure. As a result, a small amount of electricity is generated. This generated electricity makes the torch bulb glow.

What are the energy transformations taking place in the given power plant?

Electrical energy → Mechanical energy → Light energy

Mechanical energy → Electrical energy → Light energy

Heat energy → Electrical energy → Light energy

Chemical energy → Mechanical energy → Light energy

Question 9
1 / -0

Use the following information to answer the next question.

A wooden block of mass, m is given a constant force, f for time, t. The block is initially at rest.

What is the kinetic energy acquired by the block?

A

B

C

D

Question 10

1 / -0

Use the following information to answer the next question.

Cars I and II, having masses m and 2m respectively, are moving with velocities 2v and v respectively. They are brought to rest by the application of breaks. The cars take the same time and cover the same distance before coming to rest.

What is the ratio of change in kinetic energy of car I to that of car II?

1 : 2

2 : 1

1 : 4

4 : 1

Question 11
1 / -0

An object of mass four kilograms is raised to a height of 20 metres from the ground. What is the amount of potential energy stored in the object?

A
776 J

B
778 J

C
784 J

D
790 J

Question 12
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Potential energy is the energy stored in a body by virtue of its

A
motion and/or temperature

B
position and/or shape

C
velocity

D
density

Question 13
1 / -0

Use the following information to answer the next question.

Balls I and II are simultaneously dropped from a building. The masses of balls I and II are m and 2m respectively.

If air resistance is ignored, then what will be the ratio of the instantaneous velocity of ball I to that of ball II when they reach the halfway mark?

A
1 : 1

B
2 : 3

C
1 : 4

D
3 : 2

Question 14
1 / -0

Use the following information to answer the next question.

A stone is dropped from a building of height, h. The stone falls freely under the action of gravity.

If the air resistance is ignored, then what will be the instantaneous velocity of the stone when it covers three-fourth of the total height?

A

B

C

D

Question 15
1 / -0

Use the following information to answer the next question.

A car is accelerated from rest in such a way that it acquires a uniform velocity of 5 m/s after covering a distance of 20 m. The mass of the car is 1200 kg.

What is the power generated by the car’s engine?

A
1875 W

B
1500 W

C
1000 W

D
1375 W

Question 16
1 / -0

Use the following information to answer the next question.

Firoze drops a stone from the top of a building. The height of the building is 30 metres and the mass of the stone is 1.5 kg.

If air resistance is ignored, then what is the difference between the total energy of the stone at 20-m and at 10-m heights from the ground?

A
0 J

B
2 J

C
4 J

D
6 J

Submit Test

Work and Energy...

Question 1

67.31 units

69.49 units

71.92 units

73.24 units

Question 2

only II is inessential

only III is inessential

both I and II are inessential

both I and III are inessential

Question 3

only II is true

only III is false

all three statements are true

all three statements are false

Question 4

1.23 J

2.56 J

3.84 J

6.14 J

Question 5

reads a book for a long time

climbs a staircase slowly

stands with a heavy load

pushes a huge rock

Question 6

Conservation of mass

Conservation of charge

Conservation of energy

Conservation of momentum

Question 7

184400 J

188400 J

194400 J

198400 J

Question 8

Electrical energy → Mechanical energy → Light energy

Mechanical energy → Electrical energy → Light energy

Heat energy → Electrical energy → Light energy

Chemical energy → Mechanical energy → Light energy

Question 9

Question 10

1 : 2

2 : 1

1 : 4

4 : 1

Question 11

776 J

778 J

784 J

790 J

Question 12

motion and/or temperature

position and/or shape

velocity

density

Question 13

1 : 1

2 : 3

1 : 4

3 : 2

Question 14

Question 15

1875 W

1500 W

1000 W

1375 W

Question 16

0 J

2 J

4 J

6 J

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