A proton is kept at rest. A positively charged particle is released from rest at a distance `d` in its field. Consider two experiments, one ini which the charged particle is also a proton and in another, a position. In the same time `t`, the work done on the two moving charged particles is

Options

A. same as the same force law is involved in the two experiments
B. less for the case of a positron, as the positron moves away more rapidly and the force on it weakens
C. more for the case of a position, as the positron moves away a larger distance
D. same as the work done by charged particle on the stationary proton

Answer

C

Explanation

(c ) Force between two protons is same as that of between proton and a positron.
As positron is much lighter than proton, it moves away through much larger distance compared to proton. We know that work done `="force" xx "distance"`. As forces are same in case of proton and positron but distance moved by positron is larger, hence, work done will be more.