why does light through prism shows rainbow colors?

Answer 1

Refraction occurs at the interface between two media. The angle of refraction is given by Snell's law:

"The ratio of the sines of the angle of incidence and refraction is equal to the ratio of the refractive indices of the respective media"

Or:

sin(theta1) / sin(theta2) = n1 / n2

where theta1 and theta2 are the angles of incidence and refraction respectively, n1 is the refractive index of the first medium and n2 is the refractive index of the second medium.

Now, the refractive index of a medium (n) is given by:

n = sqrt(epsilonr mur)

where sqrt means the square root, epsilonr and mur are the relative permittivity and permeability of the medium respectively.

The relative permittivity of a medium is a measure of the medium's electrical response. Similarly, the relative permeability is a measure of the medium's magnetic response. Together, they completely describe how a medium responds to electromagnetic radiation (light).

So why does light through a prism show rainbow colours?

Well, epsilonr (and mur) is a function of frequency of light. epsilonr is given in the drude model by:

epsilonr = 1 - (omegap^2 / (omega^2 + j Gamma omega))

where omegap is the plasma frequency of the medium, omega is the angular frequency of the electromagnetic radiation, j is the square root of -1 and Gamma is the loss.

White light is a broadband light source, i.e. it contains a range of frequencies of light. It can be seen from this that each frequency of light (and there is an infinite number of unique colours, not seven) has a different epsilonr and, consequently, a different refractive index.

This means, according to Snell's law, that each colour of light will refract at a different angle. In otherwords, all the colours will spread.

Answer 2

The dispersion of colors in a prism occurs because of something called the refractive index of the glass. Every material has a different refractive index. When light enters a material (for example, when light traveling through the air enters the glass of a prism), the difference in the refractive index of air and glass causes the light to bend. The angle of bending is different for different wavelengths of light. As the white light moves through the two faces of the prism, the different colors bend different amounts and in doing so spread out into a rainbow.

Answer 3

White light is made up of the seven colours of the rainbow, when past through a prism each colour refracts at a different angle thus seperating the white light into it's 7 colours!

Answer 4

The act of light passing through glass, any glass, will split the visible light beam (white light) into it's spectrum of colours (red, orange, yellow, etc etc).
When it passes through a prism, the light actually passes through two different panes of glass. One on the way it, where the light is defracted once. Then the seperate beams pass through another pane of glass on the way out of the prism. This spreads the coloured beams further from each other, making them easier to see.

Answer 5

The prism changes the course of the light. This is called refraction. The degree of refraction changes with the color (wavelength) of the light.

Answer 6

The light ray which comes from the sun is known as white light.Any ray which gives spectrum similar to the sunlight is refered to as white light.A white light has seven colours as you can understand it from the acronymes VIBGYOR.That's why when a white light passes through a prism It give rise to rainbow.This was first discovered by Sir Issac Newton.

Answer 7

Light rays come in different wave lengths and the different thicknesses of the prism allow those rays to be separted and then refracted onto a surface that we can see. There are more rays out there (X-ray, gamma rays, etc) but the human eye can only see the roygbv colors.

Answer 8

because lights made up of seven colours, and they're all refracted when shown throught a prism. (I think)

Answer 9

Simply because the different colours have different speeds in all other materials except space and air.

Answer 10

Colour spectrum due to refraction