To determine the distance covered by a particle undergoing Simple Harmonic Motion (SHM) in one time period, we need to understand the nature of SHM and the path traveled by the particle.
In SHM, the particle oscillates back and forth about a central point, from one extreme to the other and back again, over a defined amplitude, A.
The distance covered in one complete oscillation, or time period, is the sum of the path from the central point to one extreme, back through the central point to the opposite extreme, and then back to the central point again:
Adding these distances gives the total distance covered in one complete cycle:
A + A + A + A = 4A
Therefore, the correct answer is that the distance covered by a particle undergoing SHM in one time period is 4A.
This rules out the other options ("zero", "A", "2A"), as they do not represent the logical total distance traveled during the complete cycle of motion.