Question

A capillary tube of radius R is immersed in water and water rises in it to a height H. Mass of water in the capillary tube is M. If the radius of the tube is doubled, mass of water that will rise in the capillary tube will now be

• A. \(M\)
• B. \(2M\)
• C. \(\dfrac{M}{2}\)
• D. 4M

Hint:

In capillary rise: M ∝ R Doubling radius halves height but increases area.

Answer 1

The Correct Option is A

Step 1: Height of capillary rise h ∝ (1)/(R)
Step 2: Volume (and hence mass) M ∝ R² h ∝ R² · (1)/(R) = R
Step 3: When radius is doubled, height becomes half, so mass remains unchanged.