Question

Work of 3.0 x 10⁴ joule is required to be done in increasing the size of a soap film from 10 cm, 6 cm to 10 cm x 11 cm. The surface tension of the film is

(a) 5 x 10^-2 N/m

(b) 3 x 10^-2 N/m

(c) 1.5 x 10^-2 N/m

(d) 1.2 x 10^-2 N/m

Answer 1

Correct option (b) 3 x 10^-2 N/m

Explanation :

Surface tension,

As the soap film has two surfaces.