Question

Calculate the magnitude of capillary effect in millimeters in a glass tube of 7mm diameter, when immersed in mercury. The temperature of the liquid is 25℃ and the values of surface tension of mercury at 25℃ is 0.51 N/m. The angle of contact for mercury is 130°.

(a) 140

(b) 280

(c) 170

(d) 210

This question was posed to me in a job interview.

I need to ask this question from Surface Tension, Capillarity, Vapour Pressure and Cavitation in chapter Properties of Fluids of Fluid Mechanics

Answer 1

The correct choice is (a) 140

The explanation: Capillarity rise or fall

                     h=4*cosθ*σ/ρ*g*d

                       =4*cos130*0.51/13600*9.81*0.007

                       =140 mm.