Molecular forces exist between the molecules of a liquid in a container. The molecules on the surface have unequal force leading to a tension on the surface. If this is not compensated by a force, the equilibrium of the liquid will be a difficult task. This leads to an excess pressure on the surface. The nature of the meniscus can inform us of the direction of the excess pressure. The angle of contact of the liquid decided by the forces between the molecules, air and container can make the angle of contact.
In a meniscus of radius `r`, with excess pressure p in atmospheric pressure `p_(0)`, the force experienced is

Options

A. `(p-p_(0))pir^(3)`
B. `(p-p_(0))2pir`
C. `ppir^(2)`
D. `p_(0)2pir`

Answer

C

Explanation

Difference in pressure between the inner and outer
surface is `(p_(i)-p_(0))`. `:.` force`=(p_(i)-p_(0))pir^(2)`
Since excess pressure is given `p=(p_(i)-p_(0))`
`:. F=ppir^(3)`
So (C) is correct and the rest are incorrect.