A capillary tube of radius R is immersed in water and water rises to a height h, with mass M in the tube. If the radius is doubled to 2R, what mass of water will rise in the capillary?

Correct answer: 2 M

Solution

When r doubles to 2R, height h halves (h ∝ 1/r). New mass = rho * pi * (2R)² * (h/2) = rho * pi * 4R² * h/2 = 2 * rho * pi * R² * h = 2M.

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