A Brief Explanation of Constructive and Destructive Interference

When two waves collide, they can create a variety of outcomes. In some cases, the two waves will merge and create a new wave. In other cases, the two waves will cancel each other out and produce silence and in still other cases, the two waves will interact with each other to create interference patterns. This blog post will discuss constructive and destructive interference and how these interference patterns can be used to analyze particle collisions. Stay tuned!

What is interference?

Interference occurs when two or more waves are combined. The resultant wave is the sum of the individual waves. The term interference usually refers to the relations of waves that are coherent or correlated with each other, either because they arrive from the same source or because they have the same or nearly the same frequency. If a particle is acted on by two (or more) waves, the particle will experience a resultant interference.

Constructive and Destructive Interference

There are two types of interference: constructive and destructive.

Constructive interference occurs when the range of one wave meets the track of another wave and vice versa. The amplitudes of the two waves add together to create a larger amplitude wave. This is also known as reinforcement. Destructive interference occurs when the range of one wave meets the crest of another wave or when the trough of one wave meets the channel of another wave. The amplitudes of the two waves cancel each other out and create a smaller amplitude wave. This is also known as a cancellation.

To better understand constructive and destructive interference, let’s take a look at an example.

Examples of Constructive and Destructive Interference

Suppose you have two particle sources that emit waves. Source A emits a wave with an amplitude of +A and source B emits a wave with an amplitude of -B (where A and B are positive numbers). The resultant wave will have an amplitude of (A-B). If the amplitudes of the two waves are equal, then the resultant wave will have an amplitude of zero (A=B).

Now, let’s take a look at an example of destructive interference.

Suppose you have two particle sources that emit waves. Source A emits a wave with an amplitude of +A and source B emits a wave with an amplitude of +B (where A and B are positive numbers). The resultant wave will have an amplitude of (A+B). If the amplitudes of the two waves are equal, then the resultant wave will have an amplitude of twice the individual wave amplitudes (A=B).

As you can see, constructive interference results in a larger amplitude wave while destructive interference results in a smaller amplitude wave.

Now that we’ve seen how constructive and destructive interference work, let’s take a look at an example of how they can be used.

How constructive and destructive interference is used?

Suppose you have two slits separated by a distance d. Source A emits light with wavelength λ and passes through slit S₁. Source B emits light with wavelength λ and passes through slit S₂. The light from source A will constructively interfere with the light from source B at some points and destructively interfere at other points. The resultant wave will have a bright fringe in the middle and two dark fringes on either side. The distance between the bright fringes is given by:

d = mλ

where m is an integer. The distance between the dark fringes is given by:

d = (m+½)λ

where m is an integer.

Constructive interference appears when the path difference between the two waves is equal to an integral multiple of the wavelength. Destructive interference emerges when the path difference between the two waves is equal to an odd multiple of a half wavelength.

Conclusion

So we have seen that constructive interference occurs when the particle is at an integral multiple of a wavelength from the central maximum and destructive interference occurs when the particle is at half an integral multiple of a wavelength from the central maximum. We also saw that constructive interference results in a bright fringe and destructive interference results in a dark fringe. So, that’s a brief explanation of constructive and destructive interference. I hope this has helped you to better understand how these two types of interference work. Thanks for reading!