Diffraction and law of reflection + more optics questions

[somuchwater]

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1) So for TBR optics, one of the answer key says this : Law of reflection is independent of frequency and wavelength and independent of the refractive index of which the mirror is made. I was confused about this because when light enters a prism, isn't it broken up into different components b/c the wavelengths of the light rays are different and thus they travel at different speeds?

2) also if that's the case, how come light, when traveling through ANY medium, doesn't disperse? I know it doesn't disperse in air b/c difference in speed is not substantial through air, but how about when for example, I use my glasses?

 

[Dr. Retractor]

1. In reflection, the light is staying in the same medium, so its wavelength and frequency and therefor speed are the same.
2. I'm not sure what you mean. Light uniformly propagates through a medium because nothing is causing the light to change; its surroundings stays the same as light travels. When light enters your glasses, the distance at which light rays focus is changed because the lens on your glasses either causes light rays to converge or diverge. I think light rays do disperse when changing mediums but that is negligible.

 

[JuanPabloCastel]

1. In reflection, the light is staying in the same medium, so its wavelength and frequency and therefor speed are the same.
2. I'm not sure what you mean. Light uniformly propagates through a medium because nothing is causing the light to change; its surroundings stays the same as light travels. When light enters your glasses, the distance at which light rays focus is changed because the lens on your glasses either causes light rays to converge or diverge. I think light rays do disperse when changing mediums but that is negligible.

#2 this is the reason for having thin-lenses. If the lenses were thick there would be a chromatic aberration


Just to clarify, OP, make sure you know the difference between reflection and refraction. Reflection is when light bounces off a surface, to put it into more illustrative words.