I was watching this Feynman’s talk where he said to the reporter that “I can see you because you’re in front of me, and person on my left can see person straight to him, on my right”,because light waves are always reflecting and bouncing off, it’s our perception.
That got me to question this about light and then all electromagnetic waves in general.
Apologies if this is a stupid question, just curious.
In: Physics
While photons don’t interact with each other, they do follow the law of superposition, meaning their waves add together. If the crest of one photon wave encounters the trough of another photon wave of equal wave length and energy, they will cancel out because -x + x = 0 so the net energy and thus net intensity at that point is 0. If two like troughs or like crests encounter each other the net energy and thus intensity is double. Crests and troughs can also be called positive and negative peaks.
This can be observed in the double slit experiment, which you can look up.
If you shine a laser on a surface, hold it still and look closely you will see a sparkling effect. This is from the superposition. The light loses coherence as it reflects and scatters off the imperfections in the surface. The bright points are when two positive peaks superimpose, or add together. The darkest areas are when they add to 0.
If we illuminated a room with a single wavelength of light, because of the short wavelength of the light relative to our scale and the loss of coherence, the effect of superposition becomes more difficult to see. White light contains all of the wavelengths of visible light and we end up seeing the average of the superimposed waves. Areas where they cancel completely become statistically scarce and too small and fleeting for use to detect with our naked eye.
Latest Answers