A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V . If T is the surface tension of the liquid then:

Step-by-step solution

∆ U = S T ∆ A A i n i t i a l = 4 π r 2 n A f i n a l = 4 π R 2 ∆ A = 4 π r 2 n - 4 π R 2 4 3 π r 3 n = 4 3 π R 3 n = R 3 r 3 ∆ A = 4 π R 3 r 3 . r 2 - R 2 = 4 π R 3 r - R 3 R = 4 π R 3 3 3 1 r - 1 R ∆ A = 3 V 1 r - 1 R ∆ U = 3 V T 1 r - 1 R