Under isothermal condition, energy E is supplied to a soap bubble of surface tension `sigma` and radius r, to double the radius of the soap bubble. The value of E is

Options

A. `16 pi r^(2) sigma`
B. `24 pi r^(2)sigma`
C. `8 pi r^(2) sigma`
D. `12 pi r^(2) sigma`

Answer

A

Explanation

The energy of soap bubbles (when radius =r)
E=surface area of soap bullbe `xx` surface tension `E=4pir^(2)sigma`
Now, radius becomes a double.
Then, the value of `E=4pi(2r)^(2)sigma=16pir^(2)sigma`