Constructive vs Destructive Interference
Constructive interference and destructive interference are two concepts widely discussed in waves and vibrations. Constructive interference is the phenomenon where two waves interfere so that the resulting amplitude is greater than the amplitude of each individual wave. Destructive interference is the phenomenon where two waves interfere so that the resulting amplitude is smaller than that of individual waves. These two concepts are bound with each other and are very important in fields such as sound engineering, acoustics, waves and vibrations and various other fields. In this article, we are going to discuss what constructive interference and destructive interference are, their definitions, the similarities between constructive interference and destructive interference, the applications of these two, and finally the difference between constructive interference and destructive interference.
What is Constructive Interference?
Waves can be observed almost anywhere in nature. It is vital to have a proper understanding in the nature of waves in order to understand the nature itself. In order to understand the concept of constructive interference, one must first understand the concept of interference.
Interference is a property that is associated with the wave nature of matter. Interference can be described using the superposition principle. The superposition principle states that the net response at a given place and time is the sum of responses that are caused by each cause simultaneously. Suppose there are two waves described by the functions X1 (x, t) and X2(x, t). The net response at point x0 at time t0 is equal to Xt(x0, t0) = X1(x0, t0) + X2(x0, t0).
If the amplitudes of the two waves are equal and they are oscillating on the same plane, the maximum amplitude of the resultant wave is twice the amplitude of the original wave. The region where the amplitude is between the original amplitude and the maximum amplitude is referred as the constructive interference. The constructive interference occurs when the waves are in phase with each other.
What is Destructive Interference?
Destructive interference, as the name suggest, destructs the wave. As like the previous case, assume there are two waves with equal amplitudes oscillating on the same plane. The resultant wave from the interference of these two waves has a minimum zero amplitude. In this case, the wave completely disappears at some places. The region between the original amplitude and the minimum amplitude is known as the region of destructive interference.
Constructive Interference vs Destructive Interference
- Constructive interference gives a resultant wave with higher amplitude than the original waves; destructive interference gives a wave with lower amplitude than the original wave.
- Constructive interference and destructive interference are just two forms of interference. They can occur simultaneously for a given wave. A standing wave is a good example for constructive interference and destructive interference.
- The nodes of a standing wave represent destructive interference with zero amplitude. The antinodes of the standing wave have twice the amplitude of the original wave, and they represent constructive interference.