ICSE ICSE Class 8 - CISCE Question Bank Solutions for Physics

When does a force perform work?

State two conditions when no work is done by a force.

In which of the following cases is work being done:

1. A boy pushing a heavy rock
2. A boy climbing up the stairs
3. A coolie standing with a box on his head
4. A girl moving on the road.

A coolie is moving on a road with a luggage on his head. Does he perform work against the force of gravity? Give reason for your answer.

The moon is revolving around the earth in a circular path. How much work is done by the moon?

Write the expression for work done by a force.

Water is optically .......... than air.

Air is optically .......... than glass.

State the S.I. unit of work and define it.

When a ray of light travels from water to air, it bends ............. the normal.

State two factors on which the work done on a body depends.

When a ray of light travels from air to glass, it bends .......... the normal.

Define the term energy.

State the S.I. unit of energy.

Define 1 joule of energy.

How is work related to energy?

What are the two kinds of mechanical energy?

Match the Following

What do you understand by refraction of light?

Give reasons for the following. No work is done if a man is pushing against a wall.