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If ‘M’ is the mass of water that rises in a capillary tube of radius ‘r’, then mass of water which will rise in a capillary tube of radius ‘2r’ is
- M
- M/2
- 4M
- 2M
Correct answer: 2M
Solution
Capillary rise h = 2T cos(theta)/(rho g r) varies as 1/r. Mass = rho * pi r^2 * h varies as r^2 * (1/r) = r. Doubling the radius doubles the mass, giving 2M.
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