Does the frequency of light changes when it go through a prism

AI Thread Summary
When light passes through a prism, its frequency remains unchanged, which means the energy of the light does not change either. However, the wavelength and speed of light do change as it enters the prism due to the medium's refractive index. The colors observed are due to the different wavelengths of light being separated, but the original frequency and energy of each color remain constant. The perception of color is primarily related to wavelength, while frequency is a fundamental property that determines energy. Overall, the prism effectively separates the visible spectrum without altering the inherent properties of the light itself.
Rico L
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I know the prism can separate the light into 7 colours, but my teacher said the frequency of light changes and so as the wavelength..



if he is right... this is the bit i am not sure about

if the frequency of the light changes when it passes through a prism, does it mean the energy also changes? if it does, does it mean that when the light goes through a prism, it changes into 7 different rays which that we don't regard them as the visible light because they all have different frequency and energy ?

please correct me

i am not even sure about my basic knowledge

many thanks
 
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The frequency does not change when light enters a prism, but the intensity and energy density of the light wave decreases somewhat due to partial reflection of the wave at the air-glass boundary.
 
fluidistic said:
Ok so basically a red light (wavelength of around 600 nm) entering say a prism whose refractive index is 1.5 becomes violet (wavelength of about 400 nm) in the prism, am I right?

No, the light is still red inside the prism. The frequency of the light (or energy of the associated photons, E = hf) is what fundamentally determines the color that we perceive. We usually relate color to wavelength (in vacuum or practically, in air) because wavelength is easier to measure directly.
 
jtbell said:
No, the light is still red inside the prism. The frequency of the light (or energy of the associated photons, E = hf) is what fundamentally determines the color that we perceive. We usually relate color to wavelength (in vacuum or practically, in air) because wavelength is easier to measure directly.

Ok thank you, amazing. :smile:
 
All the frequencies ( or colors) make up white light. The prism separates them. When Newton did this he also used a second prism placed so the spectrum coming out of the first prism was mixed back into white light which exited the second prism.
 
jtbell said:
...the associated photons, E = hf

Wait a minute. Using this same logic I get an associated momentum, p=h_bar k; an increase in momentum and an imaginary mass.
 

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