Question

If the potential difference between points A and B is equal to V_A -V_B = 3 x 10⁴ Volts, how much work (in milliJoules) must be done (against the electric force) to move a change particle (Q = 3 microC) from point A to point B without changing the kinetic energy of the particle?

Answer 1

W_AB = Q(V_B-V_A) = (3 x 10^-6 C)(3 x 10⁴ V) = 9 x 10^-2 J = 90 microC. We know that the work done against the electric field must be negative since the particle will fall from high potential to low potential