Question

Calculate the work done in blowing a soap bubble from a radius of 2cm to 3cm. The surface tension of the soap solution is 30 dyne/cm.

Answer 1

Surface tension of solution(S) = 6/100 N/m = 0.06 N/m

initial radius(r) = 2 cm = 0.02 m

final radius(R) = 5 cm = 0.05m

Work done = S× 4π(R² - r²)

⇒ W = 0.06×4×π(0.05² - 0.02²)

⇒ W = 0.24π(0.0025 - 0.0004) J

⇒ W = 0.00158 J

Work done is 0.00158 J

hpoe you understand