Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

726.

When two mirrors are placed at an angle of 90º to each other, how many images will be formed when an object is placed in front of the mirrors

A.

5

B.

4

C.

3

D.

2

Correct answer is C

When two mirror are inclined at an angle θ, the number of images formed, n = \(\frac{360}{\theta}\) − 1

∴ since \(\theta\) = 90o

∴ \(\frac{360}{\theta}\) − 1

= 4 − 1

= 3

727.

The action of blotting paper on ink is due to

A.

diffusion

B.

osmosis

C.

capillarity

D.

surface tension

Correct answer is C

 

Capillarity is the tendency of a liquid to rise or fall in a narrow tube and it explains why a blotting paper absorbs ink

728.

What is the speed of a body vibrating at 50 cyclic per second

A.

100 πrads\(_{−1}\)

B.

200 πrads\(_{−1}\)

C.

50 πrads\(_{−1}\)

D.

400 πrads\(_{−1}\)

Correct answer is A

1 cycle = 360° = 2π rad

∴ 50 cycle = 2 π rad × 50 = 100 πrad

∴ = angular speed = 50 cycles per seconds = 100 π rads\(_{−1}\)

729.

The instrument to measure the relative density of liquid is

A.

thermometer

B.

hydrometer

C.

spring balance

D.

beaker

Correct answer is B

Thermometer is used to measure temperature
Hydrometer is used to measure relative density of liquid.
Spring balance is used to measure the weight of an object
Beaker is used to measure or take volume of a liquid

730.

It is known that a neutron exists in a light atomic nucleus
Which of the following also exists in the nucleus?

A.

An electron

B.

A β - particle

C.

β - particle

D.

proton

Correct answer is D

Nucleus of atom is made up of neutron and proton