Question

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 for liquid is $T$ & angle of contact is $1^o$ then rise of liquid between the plates due to capillary will be :

• A. $\frac{T\cos 1^o}{xd}$
• B. $\frac{2T\cos 1^o}{xdg}$
• C. $\frac{2T}{xdg\cos 1^o}$
• D. $\frac{T\cos 1^o}{xdg}$

Answer 1

The correct option is B $\frac{2T\cos 1^o}{xdg}$

By balancing the surface tension force with the weight
$T\times 2l\times \cos \left(1^o\right)=xlhdg$
$\therefore h=\frac{2Tl\cos \left(1^o\right)}{xdg}$ where $l$ is the breadth of the plate and $x$ is the distance between the plates