Question

The work done in blowing a soap bubble of radius $0.2m$, given that the surface tension of soap solution is $60\times {10}^{-3}N/m$ is :

• A. $24\pi \times {10}^{-2}J$
• B. $4\pi \times {10}^{-4}J$
• C. $96\pi \times {10}^{-4}J$
• D. $1.92\pi \times {10}^{-2}J$

Answer 1

The correct option is D $1.92\pi \times {10}^{-2}J$

$W=T\Delta A=T\times 2\left[4\pi R^2\right]=T\times 8\pi R^2$

$W=60\times {10}^{-3}\times 8\pi \times (0.2{)}^2=1.92\pi {10}^{-2}J$