A charge is moved in an electric field of a fixed charge distribution from point A to another point B slowly. The work done by external agent in doing so is 100J . What is the change in potential energy of the charge as it moves from A to B ? What is the work done by the electric field of the charge distribution as the charge moves from A to B ?

Explanation

`W_("ext") = DeltaU= U_(B)-U_(A)=100 J`
As `barF_("ext")=-barF_(E)` for the charge to move slowly so
`W_(E)=-W_("ext")= - 100J`