Question

) (a) Find the energy density due to a charged sphere which is located in an empty space. This sphere is a conductor and has a charge of 3.6 C and a radius of 2.15 m. This energy density should be written in terms of of the distance r from the sphere’s center. (b) Use this energy density to find the system’s total energy. To get full credit, use an integral to solve this problem.

Answer 1

a) The energy density is given by [E = electric field at a distance r from the sphere due to the sphere]

therefore at a distance r, the energy density is =

b) Consider a spherical element of radius r and thickness dr.

the energy in the element is [dV = volume of element]

      [answer]

therefore total energy stored in the system is :

[R = radius of sphere]

= [answer]