B M Sharma Solutions for Chapter: Properties of Matter, Exercise 3: DPP 5.3

Calculate the force required to separate two glass plates of area ${10}^{-2}{\mathrm{m}}^2$ with a film of water $0.05 \mathrm{mm}$ thick between them. (Surface tension of water is $70\times {10}^{-3}\mathrm{N} {\mathrm{m}}^{-1}$)

A wooden stick $2\mathrm{ }\mathrm{m}$ long is floating on the surface of water. The surface tension of water $0.07\mathrm{ }\mathrm{N} {\mathrm{m}}^{-1}$. By putting soap solution on one side of the stick, the surface tension is reduced to $0.06 \mathrm{N} {\mathrm{m}}^{-1}$. Calculate the net force on the stick.

Calculate the force required to take out a flat circular plate(light) of radius $2 \mathrm{cm}$ from the surface of water. (the surface tension of water is $70 \mathrm{dyne} {\mathrm{cm}}^{-1}$)

Two droplets merge with each other and form a large droplet. Discuss the energy in this process.

The surface tension of a liquid is $5\mathrm{ }\mathrm{N} {\mathrm{m}}^{-1}$. If a thin film of the area $0.02{\mathrm{m}}^2$ is formed on a loop, then what will be its surface energy.

If work $W$ is done in blowing a bubble of radius $R$ from a soap solution, then calculate the work done in blowing a bubble of radius $2R$ from the same solution.

If two identical mercury drops are combined to form a single drop, then calculate its temperature.

If the surface tension of a liquid is $T$, then calculate the gain in surface energy, for an increase in liquid surface by $A$.