Distance between centres of two spheres A andB, each of radius R is r as shown in figure`-1.450`. SphereB has a spherical cavity of radius `R//2` such that distance of centre of cavity is (r-R/2) from the centre of sphere A and `R//2` from the centre of sphere B. Di-electric constant of material of each sphere is K = I and material of each sphere has a uniform charge density· p per unit volume. Calculate interaction energy of the two spheres :

Answer

`(pirho^(2)R^(6)(7r-4R))/(9epsi_(0)r(2r-R))`