Q22 of 39 Page 300

A capillary tube of radius 0.50 mm is dipped vertically in a pot of water. Find the difference between the pressure of the water in the tube 5.0 cm below the surface and the atmospheric pressure. Surface tension of water = 0.075 N m-2.

190 N m-2

Given, surface tension of water,


Radius of the capillary tube,


As the liquid is water, it will concave upwards.


The pressure is given by



Pressure at a depth of 5 cm is


Let the pressure of water just below surface be P.


The difference is pressure thus becomes,



More from this chapter

All 39 →
20

The lower end of a capillary tube is immersed in mercury. The level of mercury in the tube is found to be 2 cm below the outer level. If the same tube is immersed in water, up to what height will the water rise in the capillary?

 21

A barometer is constructed with its tube having radius 1.0 mm Assume that the surface of mercury in the tube is spherical in shape. if the atmospheric pressure is equal to 76 cm of mercury, what will be the height raised in the barometer tube? The contact angle of mercury with glass = 135° and surface tension of mercury = 0.465 N m-1. Density of mercury 13600 kg m-3.

 23

Find the surface energy of water kept in a cylindrical vessel of radius 6.0 cm. Surface tension of water 0.075 J m-2.

 24

A drop of mercury of radius 2 mm is split into 8 identical droplets. Find the increase in surface energy. Surface tension of mercury 0.465 J m-2.