**CBSE Class 11 Physics – MCQ and Online Tests – Unit 6 – Work, Energy and Power**

Every year CBSE schools conducts Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standard’s subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.

**CBSE Class 11 Physics – MCQ and Online Tests – Unit 6 – Work, Energy and Power**

Question 1.

A marble moving with some velocity collides perfectly elastically head-on with another marble at rest having mass 1.5 times the mass of the colliding marble. The percentage of kinetic energy by the colliding marble after the collision is

(a) 4

(b) 25

(c) 44

(d) 67

## Answer

Answer: (a) 4

Question 2.

A body of mass 100 kg falls from a height of 10 m. Its increase in kinetic energy is

(a) 9800 J

(b) 1000 J

(c) 5000 J

(d) 3000 J

## Answer

Answer: (a) 9800 J

Question 3.

A body of mass 20 kg is initially at a height of 3 m above the ground . It is lifted to a height of 2 m from that position. Its increase in potential energy is

(a) 100 J

(b) 392 J

(c) 60 J

(d) -100 J

## Answer

Answer: (b) 392 J

Question 4.

A body of mass 10 kg is travelling with uniform speed of 5 m/s. Its kinetic energy is

(a) 25 J

(b) 125 J

(c) 1250 J

(d) 1000 J

## Answer

Answer: (b) 125 J

Question 5.

A ball is dropped from a height of 1 m. If the coeffcient of restitution between the surface and ball is 0.6, the ball rebounds to a height of

(a) 0.6 m

(b) 0.4 m

(c) 1 m

(d) 0.36 m

## Answer

Answer: (d) 0.36 m

Question 6.

A quantity of work of 1000 J is done in 2 seconds. The power utilised is

(a) 998 W

(b) 1002 W

(c) 2000 W

(d) 500 W

## Answer

Answer: (d) 500 W

Question 7.

When the linear momentum of a particle is increased by 1% its kinetic energy increases by x%. When the kinetic energy of the particle is increased by 300%, its linear momentum increases by y%. The ratio of y to x is

(a) 300

(b) 150

(c) 100

(d) 50

## Answer

Answer: (d) 50

Question 8.

A solid cylinder of length 1 m and diameter of cross section y 100 cms is first placed with its axis vertical its then slowly inclined till its axis is horizontal. The loss in its potential energy if the mass of the cylinder is 10 kg is

(a) 5g J

(b) 10g J

(c) Zero

(d) g J

## Answer

Answer: (c) Zero

Question 9.

A body of mass 10 kg moving at a height of 2 m, with uniform speed of 2 m/s. Its total energy is

(a) 316 J

(b) 216 J

(c) 116 J

(d) 392 J

## Answer

Answer: (b) 216 J

Question 10.

Two masses 1 g and 4 g are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is

(a) 4 : 1

(b) 1 : 2

(c) 0 : 1

(d) 1 : 6

## Answer

Answer: (b) 1 : 2

Question 11.

A man of 60 kg weight is standing at rest on a platform. He jumps up vertically a distance of 1 m and the platform at the same instant moves horizontally forward with the result that the man lands 1 meter behind the point on the platfrom from where the took the jump the total work done by the man at the instant he lands is

(a) 300 J

(b) 150 J

(c) 600 J

(d) zero

## Answer

Answer: (c) 600 J

Question 12.

A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?

(a) 7.2 J

(b) 3.6 J

(c) 120 J

(d) 1200 J

## Answer

Answer: (b) 3.6 J

Question 13.

A man of 60 kg weight is standing at rest on a platform. He jumps up vertically a distance of 1 m and the platform at the same instant moves horizontally forward with the result that the man lands 1 meter behind the point on the platfrom from where the took the jump the total work done by the man at the instant he lands is

(a) 300 J

(b) 150 J

(c) 600 J

(d) zero

## Answer

Answer: (c) 600 J

Question 14.

A ball is dropped from a height of 1 m. If the coeffcient of restitution between the surface and ball is 0.6, the ball rebounds to a height of

(a) 0.6 m

(b) 0.4 m

(c) 1 m

(d) 0.36 m

## Answer

Answer: (d) 0.36 m

Question 15.

An electric heater of rating 1000 W is used for 5 hrs per day for 20 days. The electrical energy utilised is

(a) 150 kWh

(b) 200 kWh

(c) 100 kWh

(d) 300 kWh

## Answer

Answer: (c) 100 kWh

Question 16.

An isolated particle of mass m is moving in a horizontal plane (x-y), along the x-axis, at a certain height above the ground. It suddenly explodes into two fragments of masses m/4 and 3m/4 . An instant later, the smaller fragment is at y = + 15 cm. The larger fragment at this instant is at

(a) y = -5 cm

(b) y = +20 cm

(c) y = +5 cm

(d) y = -20 cm

## Answer

Answer: (a) y = -5 cm

Question 17.

A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?

(a) 7.2 J

(b) 3.6 J

(c) 120 J

(d) 1200 J

## Answer

Answer: (b) 3.6 J

Question 18.

A body of mass 20 kg is initially at a height of 3 m above the ground. It is lifted to a height of 2 m from that position. Its increase in potential energy is

(a) 100 J

(b) 392 J

(c) 60 J

(d) -100 J

## Answer

Answer: (b) 392 J

Question 19.

A body of mass 10 kg is moved parallel to the ground, through a distance of 2 m. The work done against gravitational force is

(a) 196 J

(b) -196 J

(c) 20 J

(d) zero

## Answer

Answer: (d) zero

Question 20.

A body of mass 10 kg is initially at a height of 20 m above the ground. It falls to a height of 5 m above the ground. Its potential energy in the new position is

(a) 490 J

(b) 50 J

(c) 100 J

(d) 300 J

## Answer

Answer: (a) 490 J

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