Question

Water rises to a height of `10 cm` in a capillary tube and mercury falls to a depth of `3.42 cm` in the same capillary tube. If the density of mercury is `13.6 g//c.c.` and the angles of contact for mercury and for water are `135^@` and `0^@`, respectively, the ratio of surface tension for water and mercury is
A. `1: 0.15`
B. `1:3`
C. `1:6.8`
D. `1:5`

Answer 1

Correct Answer - C
`(T_(w))/(T_(Hg)) = (h_(1)rho_(1)costheta_(1))/(h_(2)rho_(2)costheta_(1))= (10xx1xx1)/(3.5335 xx13.6 xx1 xxsqrt(2)) = 1: 6.8`