set 5 MCQ Questions & Answers Detailed Explanation

Question : 1

A book is kept on the surface of a table. If the gravitational pull of the earth on the book is the force of action, then the force of reaction is exerted by

a) the table on the book

b) the book on the earth

c) the book on the table

d) the table on the earth

Question : 2

The potential energy of a freely falling object decreases progressively.

a) Sum of Potential Energy and Kinetic Energy at any point during the free fall remains constant

b) Potential energy gets converted into kinetic energy progressively

c) The law of conservation of energy is violated

d) Both (a) and (b)

Question : 3

An electrical appliance of 500 W is used for 5 hours per day. Energy consumed in 30 days will be

a) 75 kW h

b) 25 kW h

c) 2.5 kW h

d) None of these

Question : 4

Consider the following statements :

1. Copernicus discovered that the earth moves around the sun.
2. An astronaut cannot use a straw to sip a drink on the surface of the moon.
3. The S.I. unit of weight is kilogram.

a) 2 and 3

b) 1 and 2

c) 1 and 3

d) 1, 2 and 3

Question : 5

If a light body and a heavy body have equal momentum, then

a) the kinetic energy of the lighter body is equal to the kinetic energy of the heavier body

b) the lighter body has lesser kinetic energy than the heavier body

c) the lighter body has greater energy than the heavier body

d) the kinetic energy of both the bodies are independent of momentum.

Question : 6

Assertion (A):
A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R):
If no external force acts on a system, its momentum cannot change.
Code

a) (A) is true, but (R) is false

b) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

c) Both (A) and (R) are true and (R) is the correct explanation of (A)

d) (A) is false, but (R) is true