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. (a) `0.2pimJ`
B. (b) `2pimJ`
C. (c) `0.4pimJ`
D. (d) `4pimJ`

Answer 1

Correct Answer - C
W=Tx change in surface area
`W=2T4pi[(5^2)-(3)^2]xx10^4`
`=2xx0.03xx4pi[25-9]xx10^-4J=0.4pixx10^3J`
`=0.4pimJ`