Question

A moving electron approaches a proton what will happen to the potential energy of this system?

• A. Will remain constant
• B. Will increase
• C. Will decrease
• D. May increase or decrease

Answer 1

The correct option is B Will increase

It is expected to decrease but it increases.

$U=\frac{q_1{q}_2}{x^2}$ here $U$ is negative.

$U=\frac{-k{q}^2}{x^2}$

$\frac{dU}{dx}=\frac{2k{q}^2}{x^2}$

$U$ is increasing while $x$ is decreasing and irrespective of charge.