water rises in the height of 10 cm in capillry tube and mercury falls to a depth of 3.112 cm in the same capillary tube If the density of mercury is 13.6gm/cc and the angle of contact for mercury is 135 degree then ratio surface tensionof waterand mercury is

Let a liquid of density ρ rise a height h in a capillary of raduis r, then we can write

hrρg = 2Tcosθ

where T is surface tension of that liquid and θ is angle of contact.

Let T_m and T_w be the surface tension of water and mercury.

T_m/T_{w = [(3.112 * 13.6)/(10 * 1)] * [cos}θ_{w / cos(135⁰)]                (}θw is the angle of contact of water₎

         = 5.98*cosθ_w