Physics

Problem

Two point charges

+5\,\mu\text{C}

and

-5\,\mu\text{C}

are separated by

12\,\text{cm}

in vacuum. (i) Calculate the initial potential energy of the system. (ii) The negative charge is slowly taken to infinity while the positive charge remains fixed. Find the work done by an external agent during this process. (iii) Show that the change in potential energy of the system equals the negative of the work done by the electric field, and comment on the conservation of energy for the combined system and external agent. Take

1/4\pi\epsilon_0 = 9 \times 10^9\,\text{N m}^2\text{ C}^{-2}

Browse the problem library