Question

Two identical soap bubbles each of radius r and of the same surface tension T combine to form a new soap bubble of radius R. The two bubbles contain air at the same temperature. If the atmospheric pressure is p₀ then find the surface tension T of the soap solution in terms of p₀ , r and R. Assume process is isothermal. 

Answer 1

Total number of moles of air in the two soap bubbles = number of moles of air in the resulting bubble.