Question

A student has an isolated system of charged particles. The student wants to calculate the change ΔUE in the electric potential energy of the system between two instants in time but cannot do that directly, since the student does not have any information about the magnitude of the charges. Which of the following correctly describes a mathematical routine, if any, that can be used to determine ΔUE? Gravitational effects are negligible.

(A) Calculate the change AK in the total kinetic energy of the particles. This will be equal to - AUE
( B ) Calculate the change AK in the total kinetic energy of the particles. This will be equal to AUE
с Calculate the average kinetic energy Kavy of the particles during the time interval between the two instants. This will be equal to AUE-
(D) The change in electric potential energy of the system cannot be determined without knowing the magnitudes of the charges.

Answer 1

Option A - Calculate the change AK in the total kinetic energy of the particles. This will be equal to - AUE

Step-by-step explanation:

Option A is correct as increase in kinetic energy of the system will lead to exact decrease in potential energy of the system.

For example if all the charges are of same sign, these will try to go away from each other and hence these will be accelerated to increase their velocity. The increase in velocity will lead to increase in kinetic energy but in the same time as these are separated by more distance; so systems potential energy will decrease.