Q. A capillary tube when immersed vertically in a liquid records a rise of 3 cm. If the tube is held immersed in the liquid at an angle of $ 60{}^\circ $ with the vertical, the length of the liquid column along the tube will be:
EAMCETEAMCET 1996
Solution:
If capillary tube is fitted from the vertical angle $ \theta , $ then vertical height h or liquid column remains same but the length of liquid in capillary increases such that
$ \cos \theta =\frac{h}{l} $ $ \Rightarrow $ $ l=\frac{h}{\cos \theta } $ ..(1) Now, putting the given values of h and 9 in Eq.(1) $ l=\frac{3}{\cos 60}=\frac{3}{1/2}=6cm $
