Question

Work done in increasing the size of a soap bubble from a radius of 3cm to 5cm is nearly (Surface tension of soap solution `=0.03Nm^-1`)
A. `0.2pimJ`
B. `2pimJ`
C. `0.4pimJ`
D. `4pimJ`

Answer 1

Correct Answer - C
Work done `=` change in surface energy
`impliesW=2Txx4pi(R_(2)^(2)-R_(1)^(2))`
`=2xx0.03xx4pi[(5)^(2)-(3)^(2)]xx10^(-4)J=0.4pimJ`