Question

The excess pressure inside a soap bubble is four times the excess pressure inside a moving soap bubble. What is the ratio of the first and second bubble?

Answer 1

Let r₁ and r₂ be radius of soap bubbles. Excess pressure in them are

\(\frac{4σ}{r_1}\) and \(\frac{4σ}{r_2}\) where σ is surface tension.

Given P₁ = 4P₂ \(\frac{4σ}{r_1}\) = 4\(\frac{4σ}{r_2}\)

ratio of volume of I to II