12 - 06 Surface Tension - 01

Calculate the force required to take away a flat circular plate of radius 0.01 m from the surface of water. The surface tension of water is 0.075 N / m

Solution:

Given:

Radius of circular plate           =       r        =       0.01 m       

Surface Tension                       =       T       =       0.075 N / m

Force                                       =       F       =       ?

Surface tension:

          The force per unit length acting at right angle to imaginary line drawn on a free surface of liquid is called surface tension.

i . e.

T = F / L

Therefore,

F = T L

F = T X ( 2 π r)

F = 0.075 X 2 X π X 0.01

F = 0.004713 N

The force required to take away a flat circular plate of radius 0.01 m from the surface of water is F = 0.004713 newton.