Question

a soap bubble is blown to increase its radius by 10 percent.the change in its surface energy

Answer 1

Dear Student,

◆ Answer -

Change in surface energy = + 21 %

● Explanation -

Surface energy of the bubble is calculated as -

S = T × A

Assuming surface tension to be constant,

S ∝ A

Therefore,

S'/S = A'/A

S'/S = πr'^2 / πr^2

S'/S = (r'/r)^2

S'/S = (1.1r/r)^2

S'/S = 1.21

Thus, increase in surface energy is -

∆S/S = (1.21 - 1) 100 %

∆S/S = 21 %

Therefore, change in surface energy is +21%.