What is the potential energy of the soap film formed on a frame of area $4\times 10^{-3}{m}^2?$ If the area of the film is reduced by half, the change in its potential energy will be ( surface tension of the soap solution is $40\times 10^{-5}H/m)$

A metallic shpere of radius $1.0\times 10^{-3}m$ and density $1.0\times 10^{4}kg/m^3$ enters a tank of water after a free fall, falling through a distance of h in the earth's gravitational field. If its velocity remains unchanged after entering water, determine the value of h.

[Given : coefficient of viscosity of water = $1.0\times 10^{-3}N-s/m^2,g=10m/s^2$ and density of water = $1.0\times 10^{3}kg/m^3$]