Question

A tube with a diameter of 6.45 mm was placed in a liquid with a density of 998 kg / m3 and it was observed that the liquid increased by 1.44 mm in the tube. Find the surface tension of the fluid [N / m] by taking the contact angle 15 ° between the liquid and the tube surface.

Answer 1

Given data :

• Diameter of tube, D = 6.45 mm = 0.00645 m
• Density of liquid, = 998
• Increase in Height of liquid, H = 1.44 mm = 0.00144 m
• Contact angle between liquid and surface of the tube,

Now, if we put a tube in the liquid there will be rise or will be fall in the tube. This phenomena is known as Capillary Action.

It is due to cohesion and adhesion between the liquid and tube surface.

The value of rise or fall of liquid in the tube is given by,

  

Where, = Surface tension of liquid ( N/m )

= Contact angle between the liquid and surface of Tube ( degree )

= Density of liquid ( )

D = Diameter of tube ( m )

g = Gravitational acceleartion ( )

Now, substitute all the given values,

  

So,

So,   

So,

So,   

So, Surface tension of liquid is 0.0235352 N/m .