The radius of a soap bubble is increased from R to 2R. Work done in this process in terms of surface tension is

1. $24{\mathrm{\pi R}}^2\mathrm{S}$

2. $48{\mathrm{\pi R}}^2\mathrm{S}$

3. $12{\mathrm{\pi R}}^2\mathrm{S}$

4. $36{\mathrm{\pi R}}^2\mathrm{S}$

When a large bubble rises from the bottom of a lake to the surface, its radius doubles. If atmospheric pressure is equal to that of a column of water height H, then the depth of the lake is

1. H

2. 2H

3. 7H

4. 8H

If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake

1. 10m

2. 20m

3. 60m

4. 30m

In capillary tube, pressure below the curved surface of water will be 

1. Equal to atmospheric

2. Equal to upper side pressure

3. More than upper side pressure

4. Lesser than upper side pressure

Two bubbles A and B are joined through a narrow tube where bubble A is bigger. Then 

1. The size of A will increase

2. The size of B will increase

3. The size of B will increase until the pressure equals

4. None of these

Two soap bubbles have different radii but their surface tension is the same. Mark the correct statement

1. Internal pressure of the smaller bubble is higher than the internal pressure of the larger bubble

2. Pressure of the larger bubble is higher than the smaller bubble

3. Both bubbles have the same internal pressure

4. None of the above

If the excess pressure inside a soap bubble is balanced by oil column of height 2 mm, then the surface tension of soap solution will be (r = 1 cm and density d = 0.8 gm/cc)

1. 3.9 N/m                 

2. $3.9\times {10}^{-2}<mspace\; width="1em"></mspace>\mathrm{N}/\mathrm{m}$

3. $3.9\times {10}^{-3}<mspace\; width="1em"></mspace>\mathrm{N}/\mathrm{m}$       

4. 3.9 dyne/m

Due to capillary action, a liquid will rise in a tube, if the angle of contact is 

1. Acute

2. Obtuse

3. 90°

4. Zero

Two capillary tubes P and Q are dipped in water. The height of water level in capillary P is 2/3 to the height in Q capillary. The ratio of their diameters is

1. 2 : 3                           

2. 3 : 2

3. 3 : 4                           

4. 4 : 3

By inserting a capillary tube up to a depth l in water, the water rises to a height of h ( h<l). If the lower end of the capillary is closed inside the water and the capillary is taken out and closed-end opened, to what height the water will remain in the tube?

1. Zero

2. l+h 

3. 2h

4. h