The force required to separate two glass plates of area ${10}^{-2}{\mathrm{m}}^2$ with a film of water 0.05 mm thick between them, is (Surface tension of water is $70\times {10}^{-3 }$N/m)

(a) 28 N                         (b) 14 N
(c) 50 N                         (d) 38 N 

Oil spreads over the surface of water whereas water does not spread over the surface of the oil, due to

(1) Surface tension of water is very high

(2) Surface tension of water is very low

(3) Viscosity of oil is high

(4) The viscosity of water is high

Cohesive force is experienced between 

(1) Magnetic substances

(2) Molecules of different substances

(3) Molecules of same substances

(4) None of these

The property utilized in the manufacture of lead shots is

1. Specific weight of liquid lead

2. Specific gravity of liquid lead

3. Compressibility of liquid lead

4. Surface tension of liquid lead

The dimensions of surface tension are

(1) $\left[{\mathrm{MLT}}^{-1}\right]$                 

(2) $\left[{\mathrm{ML}}^2{\mathrm{T}}^{-2}\right]$

(3) $\left[{\mathrm{ML}}^0{\mathrm{T}}^{-2}\right]$                 

(4) $\left[{\mathrm{ML}}^1{\mathrm{T}}^{-2}\right]$This quantity S is the magnitude of surface
tension

A wooden stick 2 m long is floating on the surface of the water. The surface tension of water is 0.07 N/m. By putting soap solution on one side of the stick, the surface tension is reduced to 0.06 N/m. The net force on the stick due to surface tension will be:

Surface tension may be defined as 

(1) The work done per unit area in increasing the surface area of a liquid under isothermal condition

(2) The work done per unit area in increasing the surface area of a liquid under adiabatic condition

(3) The work done per unit area in increasing the surface area of a liquid under both isothermal and adiabatic conditions

(4) Free surface energy per unit volume

The energy needed to break a drop of radius \(R\) into \(n\) drops of radii \(r\) is given by:
1. \(4 πT ( nr ^2 - R ^2 )\)
2. \(\frac{4}{3} \pi \left(r^{3} n - R^{2}\right)\)
3. \(4 πT \left(R^{2} -nr^{2}\right)\)
4. \(4 πT \left(nr^{2}+R^{2} \right)\)$$

The potential energy of a molecule on the surface of liquid compared to one inside the liquid is  -
(1) Zero                                             

(2) Smaller

(3) The same                                     

(4) Greater

Two droplets merge with each other and forms a large droplet. In this process

(1) Energy is liberated

(2) Energy is absorbed

(3) Neither liberated nor absorbed

(4) Some mass is converted into energy