Question Detail
Question
A capillary tube of radius of cross section 0.42 mm is dipped vertically inside a liquid of surface tension coefficient 0.085 Nm⁻¹. The angle of contact of the liquid with the wall of capillary tube is 32° and the density of the liquid is 1260 kgm⁻³. Calculate the height which the liquid rise or fall.
Correct Answer
Option A is the correct answer.
Detailed Explanation
Using h = (2γ cos θ)/(ρgr). r = 0.42 × 10⁻³ m, γ = 0.085, θ = 32°, cos 32° = 0.848, ρ = 1260, g = 9.8. h = (2×0.085×0.848)/(1260×9.8×0.42×10⁻³) = (0.14416)/(1260×9.8×0.00042) = 0.14416/(1260×0.004116) = 0.14416/5.186 = 0.0278 m = 2.78 cm.
Hint
Capillary rise formula: h = (2γ cos θ)/(ρgr).