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### Wave Particles Duality of Matter

Posted: Fri Oct 12, 2018 10:32 pm
Hello, I am having trouble understanding the clear differences between a destructive interference and a constructive interference.

What is the difference between destructive and constructive interference?

### Re: Wave Particles Duality of Matter

Posted: Fri Oct 12, 2018 11:28 pm
Constructive inference is when two waves interact "in phase," or when their peaks line up together and their troughs line up together. this results in a combined wave of greater amplitude. Think of an ocean wave, if two little waves combine they make a bigger wave. Conversely, destructive interference is when two waves interact "out of phase," or when the peak of one wave lines up with the trough of another wave. When these waves combine, the resulting wave will have lower amplitude. Think of an ocean wave that hits a wall and bounces back on itself, becoming smaller as the high part of the original wave is leveled out by the low part trailing behind it.

### Re: Wave Particles Duality of Matter

Posted: Fri Oct 12, 2018 11:44 pm
So then what exactly are diffraction patterns and how do constructive and destructive interference affect them?

### Re: Wave Particles Duality of Matter

Posted: Sat Oct 13, 2018 12:48 am
Diffraction patterns are a result of interacting waves, meaning they mainly come from the constructive intereference of waves i.e when waves are "in phase", which is when their peaks and troughs line up with each other.

As the textbook explains it, it says that a bright line appears on the detector of, for example, a light that is being shone through a screen, when there is constructive interference. Because so many waves are interacting with each other, this will result in many "bright lines" shown on the detector, which put together is what makes up the diffraction pattern.

Since destructive interference means the waves are out of phase, meaning the radiation emitted will be lessened and therefore NO bright lines will be seen, only dimmer lines or possibly no lines at all. These lines would still be present in the diffraction pattern, however they would not be as visible as the bright lines resulting from constructive interference.

### Re: Wave Particles Duality of Matter

Posted: Sat Oct 13, 2018 5:13 pm
Think about ocean waves lining up together to create a big wave (amplifying), or lining up as to cancel each other out (destroying the wave).