Question

What does the given equation: x = Asin(ky+wt+a) represent?

(a) Wave travelling along positive x direction

(b) Wave travelling along negative x direction

(c) Wave travelling along positive y direction

(d) Wave travelling along negative y direction

The question was posed to me during an interview for a job.

My question is based upon Displacement Relation in a Progressive Wave in section Waves of Physics – Class 11

Answer 1

Right answer is (d) Wave travelling along negative y direction

The explanation is: A way of looking at a travelling wave is considering the direction in which a particular value of transverse displacement moves.                                                                                                                                                For the given equation x = Asin(ky+wt+a) we have to see the direction in which x moves.                                          For eg: If we consider the amplitude A, for x =A as t increases, y should decrease.                                                                             So, we can say that the wave propagates in the negative y direction.