Question

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 is which the charged particle is a proton and in another a positron. In the same time t, the work done on the two moving charged particles is.

• 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 positron, as the positron moves away a larger distance.
• D. Same as the work done by charged particle on the stationary proton.

Answer 1

Answer: (C)

More for the case of a positron, as the positron moves away a larger distance.

Answer 2

Force between two protons = force between a proton and a positron. As positron is much lighter than proton, it moves away a larger distance compared to proton.

As work done = force × distance, therefore in the same time t, work done in case of positron is more than that case of proton.