Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by `75xx10^-4` newton force due to the weight of the liquid. If the surface tension of water is `6xx`10^-2` newton/metre the inner circumference of the capillary must be:

Options

A. `6.5 xx10^(-2)`m
B. `12.5 xx10^(-2)`m
C. `1.25 xx10^(-2)`m
D. `0.50 xx10^(-2)`m

Answer

B

Explanation

Upward force due to S.T = Weight of the lifted water
` :. 2piT xx T = mg`
` :. "Circumference " (2 pir) =(mg)/T`
` :. " Circumference " = (75 xx 10^(-4))/(6 xx 10^(-2)) = 12.5 xx 10^(-2)m`