(English Medium) ICSE Class 10 - CISCE Question Bank Solutions

When does a force do work?

A man having a box on his head, climbs up a slope and another man having an identical box walks the same distance on a levelled road.
Who does more work against the force of gravity and why?

A wave has wavelength 50 Å.

1. Name the wave.
2. State its speed in vacuum.
3. State its one use.

Two copper wires are of the same length, but one is thicker than the other. Which wire will have more resistance?

How is the unit horsepower related to the S.I. unit of power?

A fuse is rated 8A. Can it be used with an electrical appliance rated 5 KW, 200 V ? Give a reason.

What do you mean by an equilibrium of a body?

State the condition when a body is in static equilibrium.

State the condition when a body is in dynamic equilibrium.

State two condition for a body acted upon by several forces to be in equilibrium.

State the principle of moments. Give one device as an application of it

The figure shows a uniform metre rule placed on a fulcrum at its mid-point O and having a weight 40 gf at the 10 cm mark and a weight of 20 gf at the 90 cm mark.

1. Is the metre rule in equilibrium? If not how will the rule turn?
2. How can the rule be brought in equilibrium by using an additional weight of 40 gf?

State the condition when the work done by a force is positive.  Explain with the help of examples.

A body is moved in a direction opposite to the direction of force acting on it. State whether the work is done by the force or work is done against the force

When a body moves in a circular path, how much work is done by the body? Give reason.

(Hint: The body is acted upon by the centripetal force.)

A satellite revolves around the earth in a circular orbit. What is the work done by the force of gravity? Give reason.

A coolie X Carrying a load on his head climbs up a slope and another coolie Y carrying the identical load on his head move the same distance on a frictionless horizontal platform. Who does more work? Explain the reason.

The work done by a fielder when he takes a catch in a cricket match, is negative. Explain.

Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.

A light ray passes from water to

1. air, and
2. glass.

In each case, state how does the speed of light change.