Question

calculate the workdone in blowing a soap bubble of diameter 0.6 cm against the surface tension forces. Surface tension of soap bubble is $2.5\times {10}^{-2}$ N/m.

• A. $5.65\times {10}^{-6}$ J
• B. $5.65\times {10}^{-5}$ J
• C. $5.65\times {10}^{-4}$ J
• D. $5.65\times {10}^{-3}$ J

Answer 1

Answer: (A)

$5.65\times {10}^{-6}$ J

$\text{We know that}$

$T=\frac{\epsilon }{A}$

$\epsilon =T\times 2A(\because 2\text{surfaces})$

$\epsilon =2.5\times {10}^{-2}\times 2\times 4\pi \times (0.003{)}^2$

$=180\pi \times {10}^8$

$=5.65\times {10}^{-6}J$

$\text{Ans:}\left(A\right)$