Question

What should be the diameter of a soap bubble such that the excess pressure inside it is 51.2 Pa? 

[Surface tension of soap solution = 3.2 × 10^-2 N/m]

Answer 1

Data : p – p₀ = 51.2 Pa, T = 3.2 × 10^-2 N/m

Forasoapbubb1e, p – p₀ = \(\frac{4T}R\)

∴ The radius of the soap bubble should be

R = \(\frac{4T}{p-p_0}\) = \(\frac{4\times3.2\times10^{-2}}{51.2}\) = 2.5 × 10^-3 m = 2.5 mm

∴ the diameter of the soap bubble should be 2 × 2.5 = 5 mm.