# 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'?

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.

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the actual equation is c=wave length *frequency

when wave length changes only speed of light in that medium changes not frequency

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This is a brilliant question. The answer to this is:

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.

• 46
Frequency is a property of source or u can say it depends only upon the source of not on medium in which light travels.
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Reflection and refraction arises through interaction of incident light with the atomic constituents of matter. Atoms may be viewed as oscillators which take up the frequency of the external agency (light) causing forced oscillations The frequency of light emitted by a charged oscillator. Thus the frequency of scattered light equals the frequency of incident light.
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Frequency is the characterstic of the sources while the wavelength is the characterstic of the medium. When monochromatic light travels from one medium to another , it's speed changes, so it's wavelength changes but frequency remain same. Reflection and refraction arise due to interaction of incident light with atomic constitution of matter which vibrate with same frequency as that of incident light. Hence frequency remain unchanged.
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Reflection and refraction arise through interaction of incident light with the atomic constituents of matter. Atoms may be viewed asoscillators, which take up the frequency of the external agency (light) causing forced oscillations. The frequency of light emitted by a charged oscillator equals its frequency of oscillation. Thus, the frequency of scattered light equals the frequency of incident light.
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Frequency is the characterstic of the sources while the wavelength is the characterstic of the medium. When monochromatic light travels from one medium to another , it's speed changes, so it's wavelength changes but frequency remain same. Reflection and refraction arise due to interaction of incident light with atomic constitution of matter which vibrate with same frequency as that of incident light. Hence frequency remain unchanged.
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(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.

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good job guys.........
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go go...
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Reflection and refraction arise through interaction of incident light with atomic constituents of matter which vibrate with the same frequency as that of incident light. Hence frequency remains unchanged.
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