When a part of a straight capillary tube is placed vertically in a liquid, the liquid raises upto certain height h. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by 1 % each, then the height of the liquid in the tube will change b $y _____%.$
Options

Question

When a part of a straight capillary tube is placed vertically in a liquid, the liquid raises upto certain height h. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by 1 % each, then the height of the liquid in the tube will change b $y _____%.$

Options

G1 Physics · Accepted Answer

Capillary rise is h = 2T cosθ/(ρgr). For small percentage changes, with θ and g unchanged, Δh/h = ΔT/T - Δρ/ρ - Δr/r. Here, surface tension decreases by 1%: ΔT/T = -1%. Density decreases by 1%: Δρ/ρ = -1%. Radius decreases by 1%: Δr/r = -1%. Therefore, percentage change in h = (-1) - (-1) - (-1) = +1%. Hence the capillary rise increases by 1%. Correct option: D.