Question

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:

• A. 3 cm
• B. 2 $\sqrt{2}$ cm
• C. 15 cm
• D. 6 cm

Answer 1

Answer: (D)

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) $l=\frac{3}{\cos 60}=\frac{3}{1/2}=6cm$