Question

The air pressure inside a soap bubble of diameter 3.5 mm is
8 mm of water above the atmosphere. Calculate the surface tension of soap solution.​

Answer 1

pressure = 2T÷r

diameter ÷ 2 =radius

r=3.5÷2 =1.75

pressure ×r =T

T= 4.5 × 1.75 = 7.875 where T is the surface tension