The amount of work done in blowing a soap bubble such that its diameter increases from d to D is (T=surface tension of the solution)

Options

A. `2 pi (D^(2)-d^(2))S`
B. `pi(D^(2)-d^(2))S`
C. `4pi (D^(2)-d^(2))S`
D. `8pi(D^(2)-d^(2))S`

Answer

A

Explanation

Change in surface area
`=2 xx 4pi(D/2)^(2) -(d/2)^(2)=2pi(D^(2)-d^(2))`
`therefore` Work done = surface x change in area `=2piS(D^(2)-d^(2))`