The rise of a liquid in a capillary tube depends on

(a) the material

(b) the length

(c) the outer radius

(d) the inner radius of the tube

Choose the correct option:

1. (a) and (b)

2. (a), (b) and (c)

3. (a), (b) and (d)

4. All of these

The contact angle between a solid and a liquid is a property of

(a) the material of the solid

(b) the material of the liquid

(c) the shape of the solid

(d) the mass of the solid

Choose the correct option:

1. (a) and (b)

2. (b) and (c)

3. (c) and (d)

4. All of these

A liquid is contained in a vertical tube of semicircular cross-section (figure). The contact angle is zero. The forces of surface tension on the curved part and on the flat part are in ratio:

1. \(1:1\)
2. \(1:2\)
3. \(\pi:2\)
4. \(2: \pi\)

When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary.

Choose the correct option:

A solid sphere moves at a terminal velocity of 20 m s^–1 in air at a place where g = 9.8 m s^–2. The sphere is taken in a gravity-free hall having air at the same pressure and pushed down at a speed of 20 m s^–1.

(a) Its initial acceleration will be 9.8 m s^–2 downward

(b) Its initial acceleration will be 9.8 m s^–2  upward

(c) The magnitude of acceleration will decrease as the time passes

(d) It will eventually stop

Choose the correct option:

1. (a) and (b)

2. (b) and (c)

3. (a), (b) and (c)

4. (b), (c) and (d)

The properties of a surface are different from those of the bulk liquid because the surface molecules
 

Choose the correct option:

A spherical ball is dropped in a long column of a viscous liquid. The speed of the ball (\(v\)) as a function of time (\(t\)) may be best represented by the graph:

                                   
1. \(\mathrm{D}\) 
2. \(\mathrm{B}\) 
3. \(\mathrm{A}\) 
4. \(\mathrm{C}\)

A solid sphere falls with a terminal velocity of 20 m s^–1 in air. If it is allowed to fall in vacuum,

1. terminal velocity will be 20 m s^–1

2. terminal velocity will be less than 20 m s^–1

3. terminal velocity will be more than 20 m s^–1

4. there will be no terminal velocity

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

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