8000 identical water drops are combined to form a big drop. Then the ratio of the final surface energy to the initial surface energy of all the drops together is 
(1) 1 : 10                     

(2) 1 : 15

(3) 1 : 20                     

(4) 1 : 25

When two small bubbles join to form a bigger one, energy is

(1) Released

(2) Absorbed

(3) Both (1) and (2)

(4) None of these

A film of water is formed between two straight parallel wires of length 10cm each separated by 0.5 cm. If their separation is increased by 1 mm while still maintaining their parallelism, how much work will have to be done (Surface tension of water =$7.2\times {10}^{-2} \mathrm{N}/\mathrm{m}$)

(1) $7.22\times {10}^{-6} \mathrm{Joule}$

(2) $1.44\times {10}^{-5} \mathrm{Joule}$

(3) $2.88\times {10}^{-5} \mathrm{Joule}$ 

(4) $5.76\times {10}^{-5} \mathrm{Joule}$

A drop of mercury of radius 2 mm is split into 8 identical droplets. Find the increase in surface energy. (Surface tension of mercury is $0.465 \mathrm{J}/{\mathrm{m}}^2$) 

(1)$23.4 \mathrm{\mu J}$

(2) $18.5 \mathrm{\mu J}$

(3) $26.8 \mathrm{\mu J}$

(4) $16.8 \mathrm{\mu J}$

If two soap bubbles of equal radii r coalesce then the radius of curvature of interface between two bubbles will be

(1) r                                 

(2) 0

(3) Infinity                         

(4) 1/2r

The angle of contact between glass and mercury is

(1) 0°

(2) 30°

(3) 90°

(4) 135°

A mercury drop does not spread on a glass plate because the angle of contact between glass and mercury is

(1) Acute

(2) Obtuse

(3) Zero

(4) $90°$

The liquid meniscus in the capillary tube will be convex if the angle of contact is

(1) Greater than 90°

(2) Less than 90°

(3) Equal to 90°

(4) Equal to 0°

The value of contact angle for kerosene with a solid surface.

(1) 0°

(2) 90°

(3) 45°

(4) 33° 

Nature of meniscus for liquid of $0^0$ angle of contact

(1) Plane

(2) Parabolic

(3) Semi-spherical

(4) Cylindrical