metal sphere....

E inside a metal sphere = 0

dU = 0.5εE²*dV

where dU = small energy which is stored in a small volume dV

U = \int \frac{1}{2}\varepsilon _{o}E^{2}dV

E = \frac{1}{4\pi \varepsilon _{o}}\frac{Q}{r^2}\textup{ where Q = 4}\pi\varepsilon_{o}\textup{VR so E = }\frac{VR}{r^2}

dV = 4\pi r^2dr

(a) Energy from r = R to r = 2R

So, U = \int_{R}^{2R}{\frac{1}{2}\varepsilon_{o}\frac{V^{2}R^{2}}{r^{4}}*4\pi r^{2}dr}

(b) Energy stored outside r = 2R

U = \int_{2R}^{\infty }{\frac{1}{2}\varepsilon_{o}\frac{V^{2}R^{2}}{r^{4}}*4\pi r^{2}dr}

got it..thanxx