Question

A soap bubble (surface tension 30 dyne/cm) has radius of 1 cm. The work done in doubling its radius would be

Answer 1

The answer to the question is 720π ergs.

Answer 2

Dear Student,

◆ Answer -

W = 2262.6 ergs

● Explanation -

# Given -

T = 30 dyne/cm

r = 1 cm

r' = 2r

# Solution -

Surface area of small soap bubble is -

A = 8πr^2

A = 8 × 3.142 × 1^2

A = 25.14 cm^2

Surface area of soap bubble after doubling radius is -

A' = 8πr'^2

A' = 8π(2r)^2

A' = 8 × 4 × 3.142 × 1^2

A' = 100.56 cm^2

Work done in doubling the radius is -

W = T (A' - A)

W = 30 (100.56 - 25.14)

W = 2262.6 ergs

Thanks dear. Hope this helps you...