A rectangular film of liquid is expanded from $(5 \mathrm{~cm} \times 4 \mathrm{~cm})$ to $(7 \mathrm{~cm} \times 8 \mathrm{~cm})$. If the work done is $3 \times 10^{-4} \mathrm{~J}$, the surface tension of the liquid is (nearly)

A capillary tube is taken from earth's surface to moon's surface. The rise of liquid column on the moon's surface is (acceleration due to gravity on the earth's surface is six times that of moon's surface)

In air, a charged soap bubble of radius R breaks into 64 small soap bubbles of equal radius $r$. The ratio of mechanical force per unit area of big soap bubble to that of a small bubble is