The figure shows a capillary tube of radius r dipped into water. If the atmospheric pressure is P₀, the pressure at point A is pressure at point A is

1. \(P_{0}\)

2. \(P_{0}+\frac{2 S}{r}\)

3. \(P_{0}-\frac{2 S}{r}\)

4. \(P_{0}-\frac{4 S}{r}\)

The excess pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is

1. 4

2. 2

3. 1

4. 0.125

Which of the following graphs may represent the relation between the capillary rise h and the radius r of the capillary?

1.

2.

3.

4.

Water rises in a vertical capillary tube upto a length of 10 cm. If the tube is inclined at 45°, the length of water risen in the tube will be

1. 10 cm

2. 10\(\sqrt2\)cm

3. 10/\(\sqrt2\)cm

4. none of these

A 20 cm long capillary tube is dipped in water. The water rises up to 8 cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be

1. 8 cm

2. 6 cm

3. 10 cm

4. 20 cm

Viscosity is a property of:
1. liquids only
2. solids only
3. solids and liquids only
4. liquids and gases only

The force of viscosity is

1. electromagnetic

2. gravitational

3. nuclear

4. weak

The viscous force acting between two layers of a liquid is given by \(\frac FA=-\eta\frac{dv}{dz}\). This F/A may be called

1. pressure

2. longitudinal stress

3. tangential stress

4. volume stress

A raindrop falls near the surface of the earth with almost uniform velocity because

1. its weight is negligible

2. the force of surface tension balances its weight

3. the force of viscosity of air balances its weight

4. the drops are charged and atmospheric electric field balances its weight

A piece of wood is taken deep inside a long column of water and released. It will move up

1. with a constant upward acceleration

2. with a decreasing upward acceleration

3. with a deceleration

4. with a uniform velocity