Interference of Waves

The net effect of two (or more waves) meeting whilst travelling in the same medium is called wave interference.

When two waves arrive in step they reinforce and when two waves arrive out of step they cancel out. This can be shown by considering two waves travelling in opposite directions in a rope.



In Step

When two identical waves meet such that the crest and the trough of one wave completely overlaps with the crest and the trough of the second wave they are said to be in step.

Out of Step

When two identical waves meet such that the crest of one wave overlaps with the trough of the second wave and the trough overlaps the crest they are said to be out of step.