Three liquids of densities ${\rho }_1,$ ${\rho }_2$ $and$ $$ ${\rho }_3$ (with ${\rho }_1>{\rho }_2>{\rho }_3$), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact ${\theta }_1,{\theta }_2$ $and$ ${\theta }_3$ obey:

Water rises to a height h in capillary tube . If the length of capillary tube above the surface of water is made less than h, then

1. water rises upto the tip of capillary tube and then starts overflowing like a fountain
 

2. water rises upto the top of capillary tube and stays there without overflowing
 

3. water rises upto a point a little below the top and stays there
 

4. water does not rise at all
 

Spherical balls of radius 'r' are falling in a viscous fluid of viscosity '$\mathrm{\eta }$' with a velocity 'v'. The retarding viscous force acting on the spherical ball is 

(1) inversely proportional to 'r' but directly proportional to velocity 'v'.

(2) directly proportional to both radius 'r' and velocity 'v'.

(3) inversely proportional to both radius 'r' and velocity 'v'.

(4) directly proportional to 'r' but inversely proportional to 'v'.

A small sphere of mass m is dropped from a great height. After it has fallen 100 m, it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is

1. Greater than the work done by air friction in the second 100 m

2. Less than the work done by air friction in the second 100 m

3. Equal to 100 mg

4. Greater than 100 mg

A liquid is flowing in a horizontal uniform capillary tube under a constant pressure difference P. The value of pressure for which the rate of flow of the liquid is doubled when the radius and length both are doubled is

1. P                             
2. $\frac{3\mathrm{P}}{4}$
3. $\frac{\mathrm{P}}{2}$                         
4. $\frac{\mathrm{P}}{4}$