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 positron, as the positron moves away more rapidly and the force on it weakens
C. more for the case of a positron, as the positron moves away a larger distance
D. same as the work done by charged particle on the stationary proton

Answer

`(3)`

Explanation

Forces 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 x distance . As forces are same in case of proton and positron but distance moved by positron is larger, hence, work done will be more.