Question

The work done in blowing a soap bubble of radius R is W. The work done in blowing a bubble of radius 2R of the same soap solution is ______.

विकल्प

• `"W"/4`

• `"W"/2`

• 4W

• 2W

Answer 1

The work done in blowing a soap bubble of radius R is W. The work done in blowing a bubble of radius 2R of the same soap solution is 4W.

Explanation:

The work done in blowing a soap bubble,

W = T × A

where, T is the surface tension and A is the area of soap bubble.

W = T × 4πR²

W ∝ R²

So, `"W"_1/"W"_2 = "R"_1^2/"R"_2^2`

`=> "W"_2 = "W"_1 ("2R"/"R")^2` = 4W