Two parallel glass plates are dipped partly in the liquid of density 'd' keeping them vertical. If the distance between the plates is 'x', Surface tension is T and angle of contact is `theta` then rise of liquid between the plates due to capillary will be

Options

A. `(T cos theta)/(xd)`
B. `(2T cos theta)/(xdg)`
C. `(2T)/(xdg cos theta)`
D. `(T cos theta)/(xdg)`

Answer

B

Explanation

Let the width of each plate is b and due to surface tension liquid will rise upto height h, then upward force due to surface tension `= 2Tb cos theta`

Weight of the liquid eises in betweent the plates
= Vdg = (bxh)dg
Equating Eqs. (i) and (ii), we get
`2Tb cos theta = bxhdg`
`therefore" "h=(2T cos theta)/(xdg)`