Question

Charge e is uniformly spread on the surface of a sphere of radius 10^-10m. What is the total electrostatic energy of the system?

Answer 1

Total electrostatic energy of the system, PE = U =
`13.82* 10^(-19) J`

Given:

radius of sphere, r =
`10^(- 10)m`

electronic charge, e =
`1.6* 10^(-19) C`

Solution:

The total electrostatic energy of the system for a uniformly spread charge e on the sphere is given by the potential energy of the system as:

PE = U =
`(3)/(5)(q^(2))/(4\pi \epsilon_(o)r)`

The above eqn can also be written as:

PE = U =
`(3)/(5)(e^(2))/(4\pi \epsilon_(o)r)`

Putting the values in the above eqn:

PE = U =
`(3)/(5)((1.6* 10^(-19))^(2))/(4\pi * 8.85* 10^(-12)* 10^(-10))`

PE = U =
`13.82* 10^(-19) J`