Question

The angle of contact between glass and water is $0^o$ and it rises in a capillary upto 6 cm when its surface tension is 70 dyne/cm. Another liquid of surface tension 140 dyne/cm, angle of contact ${60}^o$ and relative density 2 will rise in the same capillary by:

• A. 3 cm
• B. 16 cm
• C. 12 cm
• D. 24 cm

Answer 1

The correct option is A 3 cm

Rise in capillary,
$h=\frac{2T\cos \theta }{rdg}$
$\therefore \frac{h_2}{h_1}=\frac{T_2}{T_1}\times \frac{\cos {\theta }_2}{\cos {\theta }_1}\times \frac{d_1}{d_2}\times \frac{r_1}{r_2}$
$\frac{h_2}{h_1}=\frac{140}{40}\times \frac{\cos {60}^o}{\cos 0^o}\times \frac{1}{2}\times 1$
$h_2=\frac{h_1}{2}=3cm$