Force Acting on Moving Charges: Practice Problem & Solution

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Force Acting on Moving Charges. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A): Protons are positively charged, so there is an electrostatic repulsive force between parallel beams. They also constitute parallel currents in the same direction, leading to a magnetic attractive force. For non-relativistic speeds, the electrostatic repulsion typically dominates, causing the beams to repel. So, (A) is true.

Reason (R): This is a fundamental principle of electrostatics. So, (R) is true. Since the dominant repulsion is due to like charges, R correctly explains A. Thus, both (A) and (R) are true and (R) is the correct explanation of (A).