Interference of light is a special phenomenon of light reflecting the wave nature of its. Due to the interference of light, two waves interfere with each other. In this process, where crest and crest or trough and trough meet, the amplitude of light becomes very large there. And this is called constructive interference. And where one crest and one trough meet together, we get destructive interference. Thus we get till now,
Interference is of two types.
- Constructive Interference
- Destructive Interference
Constructive Interference
As we mentioned previously, where crest and crest or trough and trough meet, the amplitude of light becomes very large there and it causes constructive interference. In another word, if two waves are conjugated in the same phase, then the interference will be constructive and it will bright point. Besides, these waves should have the same amplitude.
Destructive Interference
In the inference of light, where one crest and one trough meet together, we get destructive interference. It occurs when the waves are out of phase (they are not in the same phase). It causes darkness.
This process can be described by Young's Double Slit Experiment. Look at the picture below.
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| Source: courses.lumenlearning.com |
Difference Between Constructive and Destructive Interference
| Constructive Interference | Destructive Interference |
|---|---|
| 1. When two waves interact with each other and resulting amplitude is greater than each of those, we get constructive interference | 1. In destructive interference, two waves interact and their resulting amplitude is smaller than each of those. |
| 2. Here, two waves should be in same phase and same direction. | 2. Here, the waves should be in opposite direction. |
