Q134 / 160 · TS EAMCET 2008 · Physics
The surface tension of soap solution is $0.03 \mathrm{~N} / \mathrm{m}$. The work done in blowing to form a soap bubble of surface area $40 \mathrm{~cm}^2$, (in J), is
- A$1.2 \times 10^{-4}$
- Correct answerB$2.4 \times 10^{-4}$
- C$12 \times 10^{-4}$
- D$24 \times 10^{-4}$
Solution
In case of soap bubble
$$
\begin{aligned}
W & =T \times 2 \times \Delta A \\
& =0.03 \times 2 \times 40 \times 10^{-4} \\
& =2.4 \times 10^{-4} \mathrm{~J}
\end{aligned}
$$
Hence, the correct answer is option: 'B'.