Question

The radius of a soap bubble is r. the surface tension of soap solution is T, keeping temperature constant, the radius of the soap bubble is doubled the energy necessary for this will be-
A. `24 pi R^(2)T`
B. `8pir^(2)T`
C. `12pir^(2)T`
D. `16pir^(2)T`

Answer 1

Correct Answer - A
Energy = ` S.T xx " increase in area " `
` = T xx [ 4pi (2r)^(2) - 4 pir^(2)]xx2`
` = 24 pir^(2)T`