Embibe Experts Solutions for Chapter: Viscosity and Surface Tension, Exercise 1: Assam CEE 2017

The radius of a soap bubble is increased from $1 \mathrm{cm}$ to $2 \mathrm{cm}$. The surface tension of the solution is $0.025 \mathrm{N} {\mathrm{m}}^{-1}$. The work done on the bubble is

A metallic spherical ball of mass $M$ is dropped into a liquid and after some time it reaches a terminal velocity of $v$. If another spherical ball of mass $8M$ made of the same metal is dropped into the same liquid, then its terminal velocity will be (assume the spheres to be uniformly dense)

Two glass plates are separated by water and the distance between the plates is $0.10 \mathrm{mm}$. If the surface tension of water is $75 \mathrm{dynes} \mathrm{per} \mathrm{cm}$ and area of each plate wetted by water is $8{ \mathrm{cm}}^2$, the force applied to separate the two plates is,