A liquid of surface tension 0.08 N/m, density 800 kg/m³ and contact angle 60° rises in a capillary tube of radius 0.50 mm. Taking g = 10 m/s², the rise is N cm. Find N.

Question

G1 Physics · Accepted Answer

Capillary rise is h = [2S cosθ] / [ρgr]. Substitute S = 0.08 N/m, cos60° = 1/2, ρ = 800 kg/m³, g = 10 m/s², r = 0.50 mm = 5×10⁻⁴ m. Thus, h = [2×0.08×(1/2)] / [800×10×5×10⁻⁴]. The numerator is 0.08. The denominator is 4. Therefore, h = 0.02 m = 2 cm. Hence, N = 2.