Principle :
As waves don’t repulse each other, they overlap in the same region of the space without affecting each other. When two waves overlap, their displacements add vectorially.
Explanation :
i. Consider two waves travelling through a medium arriving at a point simultaneously.
ii. Let each wave produce its own displacement at that point independent of the others. This displacement can be given as,
y1 = displacement due to first wave.
y2 = displacement due to second wave.
iii. Then according to superposition of waves, the resultant displacement at that point is equal to the vector sum of the displacements due to all the waves.
\(∴ \vec{y} = \vec{y_1} + \vec{y_2}\)
