What is the principle of superposition?

The principle of superposition states that when two or more waves overlap in a medium, the resultant amplitude at any point is equal to the algebraic sum of the individual displacements of those waves at that same point. This means that if multiple waves are present, they can interfere with each other, leading to constructive interference when their amplitudes add together, or destructive interference when their amplitudes partially or completely cancel each other out.

This principle is foundational in wave theory because it helps to explain phenomena such as interference patterns, standing waves, and the overall behavior of waves in various contexts. The total amplitude at a point is thus directly influenced by the individual contributions of each wave, making the first choice logically sound and consistent with the known behaviors of waves.