Wave Motion - Mission WM6 Detailed Help

Destructive interference would occur when a ____. List all that apply ... .

Definition of Destructive Interference:
Interference occurs when two or more waves meet while traveling through the same medium. There are two types of interference that could take place at any given location along the medium. If at a given location, both interfering waves are displaced in the opposite direction (one is up and the other down), then destructive interference is said to occur at that location.

Definition of Wave Crest:
wave crest of a wave is a location along a medium which is displaced a maximum positive distance aboveits original resting position.
Definition of Wave Trough:
wave trough of a wave is a location along a medium which is displaced a maximum negative distance belowits original resting position.

Many students understand that destructive interference occurs at a location where a crest meets a trough. Yet they miss this question because they have the wrong conception that the size of the crest must be the same as the size of the trough. But don't be fooled! The size of the crest and trough do not need to be the same in order for it to be considered destructive interference. While there may not be complete destructive interference, it is still destructive interference.