The amount of the work done in blowing a soap bubble of radius r and surface tension `sigma`, is:

Options

A. `4pir^(2)sigma`
B. `6pir^(2)sigma`
C. `8pir^(2)sigma`
D. `sigma`

Answer

C

Explanation

The amount of work done = surface tension `xx` increase in area
`=sigmaxx2xx(4pir^2)=8pir^(2)sigma`
This is because, a soap bubble has two surface areas.