A soap bubble of radius r is blown up to form a bubble of radius 2 r under isothermal conditions. If T is the surface tension of soap solution, the energy spent in the blowing

Step-by-step solution

Initially area of soap bubble A₁=4 r^2 Under isothermal condition radius becomes 2 r , Then, area A₂=4 (2 r)^2=4 4 r^2=16 r^2 Increase in surface area A=2 (A₂-A₁ )=2 (16 r^2-4 r^2 )=24 r^2 Energy spent W=T A=T 24 r^2W=24 T r^2 ~J