PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
Three identical point charges, each of magnitude q=2.0μC, are to be assembled from very far apart into a straight line of length L=0.40m. Charge 1 will be placed at the origin, Charge 2 at x=+0.20m, and Charge 3 at x=+0.40m along the x–axis.
Assume the external agent moves the charges one at a time from infinity to their final positions, always overcoming electrostatic forces quasistatically so that no kinetic energy remains in the system when a charge is released.
(a) Calculate the work the external agent must do to bring in Charge 1 from infinity and place it at the origin.
(b) After Charge 1 is in place, determine the additional work required to bring in Charge 2 from infinity to its final position at x=+0.20m.
(c) With the first two charges fixed, calculate the additional work required to bring in Charge 3 from infinity to x=+0.40m.
(d) Compute the total electric potential energy of the three–charge system once all charges are in place.
(e) Explain qualitatively how the answer to part (d) would change, if at all, if Charge 3 had been −2.0μC instead of +2.0μC. Support your reasoning without performing a full recalculation.