Question

Radius of a soap bubble is increased from $R$ to $2R$. Work done in this process is ( $T$ is surface tension)

• A. $12\pi R^{2}T$
• B. $48\pi R^{2}T$
• C. $24\pi R^{2}T$
• D. $36\pi R^{2}T$

Answer 1

Answer: (C)

$W=$ change in surface energy
$W=2\left[4\pi (2R{)}^2-4\pi R^2\right]T$
$=24\pi R^{2}T$