Question

Work done in increasing size 10 × 11 cm from 10 cm × 6 cm of a soap film is 3.0 × 10^-4 Joule. Find out the surface tension of the film.

Answer 1

Effective increase in surface area
∆A= 2(A₂ – A₁)= 2 [10 × 11 - 10 × 6] cm²
= 2 × 10(11 – 6)cm² = 2 × 10 × 5cm²
= 100cm²
= 100 × 10^-4 m²
= 1 × 10^-2 m²