Question

The surface tension of soap solution is $\sigma .$ What is the work done in blowing soap bubble of radius $r$ ?

• A. $\pi r^2\sigma$
• B. $2\pi r^2\sigma$
• C. $4\pi r^2\sigma$
• D. $8\pi r^2\sigma$

Answer 1

Answer: (D)

Work done in blowing a soap bubble $W=\sigma \times 8\pi r^2$ as bubble has two free surfaces.