When one end of a tube of radius r is immersed vertically in a liquid of density rho, surface tension S, the rise of liquid in the tube is h and angle of contact is theta . If the tube is broken and its length is made h' (lt h), then find the value of height of rise of liquid in the tube and angle of contact.

When one end of a tube of radius r is immersed vertically in a liquid

1.	When one end of a tube of radius r is immersed vertically in a liquid of density rho, surface tension S, the rise of liquid in the tube is h and angle of contact is theta . If the tube is broken and its length is made h' (lt h), then find the value of height of rise of liquid in the tube and angle of contact.
Answer» Solution :When a capillary tube is broken at a height `H' ( LT h)`, the height of LIQUID COLUMN in the tube will be h' but the angle of contact `theta'` will CHANGE As `h=(2S cos theta)/(r rho g)` or ` (h)/(cos theta) = (2S)/(r rho g) `= a constant `:. h/(cos theta)=(h')/(cos theta') or cos theta' = (h')/(h) cos theta` or `theta' = cos ^(-1) ((h')/(h) cos theta)`.