Question

Surface tension of a soap solution is $1.9\times {10}^{-2}$ N/m. Work done in blowing a bubble of 2.0 cm diameter will be

• A. $7.6\times {10}^{-6}\pi$ joule
• B. $15.2\times {10}^{-6}\pi$ joule
• C. $1.9\times {10}^{-6}\pi$ joule
• D. $1\times {10}^{-4}$ joule

Answer 1

Answer: (B)

$15.2\times {10}^{-6}\pi$ joule

As we know,

Work done in blowing a bubble is

$W=8\pi R^{2}T$

$=8\pi \ast (1\ast {10}^{-2}{)}^2\ast 1.9\ast {10}^{-2}=15.2\ast {10}^{-6}\pi J$