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

In summary: No, the associated momentum (p) is simply the momentum of the photons after they've left the prism. It doesn't have anything to do with mass (h_bar).
  • #1
Rico L
37
0
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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  • #4
  • #5
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.
 
  • #6
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.
 
  • #7
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:
 
  • #8
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.
 
  • #9
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.
 

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

1. How does a prism affect the frequency of light?

When light enters a prism, it is refracted or bent, causing the light to spread out into different wavelengths. This results in the separation of white light into its component colors, known as the visible spectrum. The frequency of light remains the same, but the wavelength changes as it passes through the prism.

2. Does the frequency of light change when it goes through a prism?

No, the frequency of light does not change when it goes through a prism. The frequency of light is determined by its source and remains constant throughout its journey, including passing through a prism.

3. How does the angle of incidence affect the frequency of light passing through a prism?

The angle of incidence, or the angle at which light enters the prism, does not affect the frequency of light passing through a prism. It only affects the direction and intensity of the light as it is refracted and dispersed.

4. Is the frequency of light affected by the material of the prism?

No, the frequency of light is not affected by the material of the prism. However, different materials have different refractive indices, which can affect the angle of refraction and the amount of dispersion of light passing through the prism.

5. Can different colors of light have different frequencies when passing through a prism?

No, all colors of light have the same frequency as they pass through a prism. However, different colors have different wavelengths, which causes them to refract at different angles and results in the separation of colors in the visible spectrum.

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