(English Medium) ICSE Class 9 - CISCE Question Bank Solutions for Physics

What is a fluid?

What do you mean by the term fluid pressure?

How does the pressure exerted by a solid and fluid differ?

Describe a simple experiment to demonstrate that a liquid enclosed in a vessel exerts pressure in all directions.

State three factors on which the pressure at a point in a liquid depends.

Write an expression for the pressure at a point inside a liquid. Explain the meaning of the symbols used.

Deduce an expression for the pressure at depth inside a liquid.

Pressure at the free surface of a water lake is P₁, while at a point at depth h below its free surface is P₂. (a) How are P₁ and P₂ related? (b)Which is more P₁ or P₂?

Explain why a gas bubble released at the bottom of a lake grows in size as it rises to the surface of the lake.

A dam has broader walls at the bottom than at the top. Explain.

Why do sea divers need special protective suit?

State the laws of liquid pressure.

A tall vertical cylinder filled with water is kept on a horizontal table top. Two small holes A and B are made on the wall of the cylinder, A near the middle and B just Below the free surface of water. State and explain your observation.

How does the liquid pressure on a diver change if:

the diver moves to the greater depth

How does the liquid pressure on a diver change if : 

The diver moves horizontally?

The diagram below in Fig. 4.12 shows a device which makes the use of the principle of transmission of pressure.

1. Name the parts labelled by the letters X and Y.
2. Describe what happens to valves A and B and to the quantity of water in the two cylinders when the lever arm is moved down.
3. Give reasons for what happens to valves A and B in part (ii).
4. What happens when the release valve is opened?
5. What happens to valve B in cylinder P when the lever arm is moved up?
6. Give a reason for your answer in part (v).
7. State one use of the above device.

Complete the following sentence :

Pressure at a depth h in a liquid of density p is ......................

Complete the following sentence :

 Pressure is .................... in all directions about a point in a liquid.

Complete the following sentence :

Pressure at all points at the same depth is ....................

Complete the following sentence :

Pressure at a point inside the liquid is ...................... To its depth.