Water rises to a height of 10 cm in capillary tube and mercury falls to a depth of 3.42 cm in the same tube. If the density of mercury is 13.6 g `cm^(-3)` and angle of contact is 135°, the ratio of the surface tensions for water and mercury is :

Options

A. `1:5.57`
B. `1:3.57`
C. `1:6.57`
D. `:1.1.57`

Answer

C

Explanation

`(T_(omega))/(T_(m))=(h_(omega)d_(omega))/(costheta_(omega))xx(costheta_(m))/(h_(m)xxd_(m))=(10xx1xxcos135^(@))/(1xx3.42xx13.6)`
`=(10xx1)/(3.42xx1.414xx13.6)=1/(6.57)`
Correct choice is (c).