When monochromatic light is incident on a surface separating two media, the reflected & refracted light both hav the same frequency as the incident frequency.Cud u explain in detail 'why'?
I don't know much about this at 12th level.But a very basic approach is as follows.
Monochromatic light = Light of a particular single color = Light of a certain wavelength.
wavelength is inversely proportional to frequency.So frequency depends only on wavelength
So frequency will change only and only when wavelength changes.
But a monochromatic light comes out as such in both refraction in reflection.So frequency doesn't change because wavelength has not changed.
Thanks.Hope you got it and please tell me whether its correct or not.And if you get a good answer (detailed or high level answer) for this please do notify me.
When light falls on a surface, then the electron density(i.e, electrons) of the surface tends to oscillate, as they are oscillating due to an external agency(which is light), so this kind of oscillation is called FORCED OSCILLATION(class 11th), now they oscillate with the frequency they took up, i.e., with the frequency of incident light. As we have studied(chapter 8, EM waves), an oscillating charged particle is a source of EM wave. Hence, these charged oscillators scatter the light with the frequency they are having i.e., the frequency of incident light. Hence, whether reflection(scattered light goes in the same medium) takes place or refraction(scattered light goes in the second medium), in both the cases, the frequency of light will not change.
(i) Reflection and refraction arise through interaction of incident light with atomic constituents of matter which vibrate with the same frequency as that of the incident light. Hence frequency remains unchanged.
(ii) No. [Energy carried by a wave depends on the amplitude of the wave, not on the speed of wave propagation].
(iii) For a given frequency, intensity of light in the photon picture is determined by the number of photon incident normally on crossing a unit area per unit time.