Question

The surface tension of soap solution is `0.03 N//m` . The work done in blowing to from a soap bublle of surface area `40 cm^(2)`, (in J) , is
A. `2.4xx10^(-4)` J
B. `1.2xx10^(-2)` J
C. `3.6xx10^(-4)` J
D. `4.2xx10^(-2)` J

Answer 1

Correct Answer - A
Here, surface tension, `S=0.03 N m^(-1)`
Surface area =`40 cm^(2) =40xx10^(-4) m^(2)`
Work done=Surface tension `xx` change in surface area `=0.03xx2xx(40xx10^(-4))J=2.4xx10^(-4)J`