Question

Two waves of equal amplitude A, and equal frequency travel in the same direction in a medium. The amplitude of the resultant wave is

Answer 1

Correct Answer - D
Two waves of equal amplitude A and equal frequency interfere such that amplitude of the resultant waves is
`A (phi) =2 A cos (phi/2)`
From cosine graph, it can be seen that the amplitude of the resultant wave is a function of `phi` and hence, its magnitude varies between 0 and 2A.