The work done in blowing a soap bubble of a radius 0.02 cm m to radius 0.04 m will be

Options

A. `4.22 xx 10^(-4)` J
B. `5. 84 xx 10^(-4)` J
C. ` 8.45 xx 10^(-4)` J
D. ` 6. 45 xx 10^(-4)` J

Answer

C

Explanation

`dE= 4piT(R_(2)^(2)-R_(1)^(2))`
` = 12.56 xx 28 xx 10^(-3) xx 10^(-4) xx 12 xx2`
` = 0.45 xx 10^(-4)` J