A spherical drop of water has a radius of 1 mm. If the surface tension of water is $70\times {10}^{-3}$ N/m, the difference in pressures inside and outside the spherical drop is:

The property of surface tension of the liquid is due to:

In order to float a ring of area 0.04 ${\mathrm{m}}^2$ in a liquid of surface tension 75 N/m, the required surface energy will be:

Small droplets of liquid are usually more spherical in shape than the larger drops of the same liquid because:

If the excess pressure inside a soap bubble is balanced by an oil column of height of \(2\) mm, then the surface tension of the soap solution will be: (radius of the soap bubble, \(r=1\) cm and density of oil, \(d=0.8\) gm/cm³)
1. \(3.9\) N/m
2. $3.9\times {10}^{-2}$ $\mathrm{N}/\mathrm{m}$
3. $3.9\times {10}^{-3}$ $\mathrm{N}/\mathrm{m}$
4. \(3.9\) dyne/m

The energy needed to break a drop of radius R into n drops of radii r is given by:

1. $4\mathrm{\pi T}({\mathrm{nr}}^2-{\mathrm{R}}^2)$

2. $\frac{4}{3}\mathrm{\pi }({\mathrm{r}}^3\mathrm{n}-{\mathrm{R}}^2)$

3. $4\mathrm{\pi T}({\mathrm{R}}^2-{\mathrm{nr}}^2)$

4. $4\mathrm{\pi T}({\mathrm{r}}^2\mathrm{n}+{\mathrm{R}}^2)$

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:

The surface tension of a liquid is \(5\) N m^-1. If a film is held on a ring of area \(0.02\) ${\mathrm{m}}^2$, then its total surface energy is:
1. \(3\times\) ${10}^{-2}$ J
2. \(2\times\) ${10}^{-1}$ J
3. \(3\times\) ${10}^{-3}$J
4. ${10}^{-1}$ J

Two soap bubbles are connected by a tube as shown in the figure. Which of the following statement is true?
                                  

A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then:\(\text { Energy }=4 V T\left(\frac{1}{r}-\frac{1}{R}\right) \text { is released } \)