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 aligned & =4 4 r^2 & =16 r^2 aligned Increase in surface area aligned A & =2 (A₂-A₁ ) & =2 (16 r^2-4 r^2 )=24 r^2 aligned Energy spent aligned W & =T A & =T 24 r^2 or W=24 Tr ^2 ~J aligned