Destructive interference

Definition

Destructive interference occurs when two waves meet in such a way that their crests and troughs cancel each other out, resulting in a reduced or zero amplitude. This phenomenon is a result of the superposition principle.

5 Must Know Facts For Your Next Test

1. Destructive interference happens when the phase difference between the two waves is an odd multiple of $\pi$ radians (180 degrees).
2. For complete destructive interference, the amplitudes of the interfering waves must be equal.
3. It can occur in various types of waves including sound, light, and water waves.
4. The points where destructive interference occurs are called nodes in standing wave patterns.
5. Destructive interference is used in noise-canceling headphones to reduce unwanted ambient sounds.

Review Questions

• What is the condition for destructive interference to occur between two waves?
• Describe what happens to the amplitude of two interfering waves during destructive interference.
• How does destructive interference contribute to the functioning of noise-canceling headphones?

Related terms

Constructive Interference: Occurs when two waves meet and their crests and troughs align, resulting in an increased amplitude.

Superposition Principle: States that when two or more waves overlap, the resultant displacement at any point is equal to the sum of the displacements due to each individual wave.

Node: A point along a standing wave where the wave has minimal amplitude due to destructive interference.