# Diffraction of blue and red light on a prism

• khondowe
In summary, the emergent ray for blue light is refracted more than red light rays and its path lies on the boundary of the prism after being diffracted. The critical angle (c) is formed and it is too large for the refracted blue light ray to pass through that face. The refractive index and critical angle for blue light depend on its wavelength. It is suggested to change the term 'diffraction' to 'refraction' in the title of the post.

#### khondowe

Could someone help me with the path taken by the emergent ray for blue light if it is refracted most than red light rays.the emergent ray for the red light lies on the boundary of the prism after being diffracted and forms the criticle angle(c). Is the path taken by the refracted blue light ray going to towards the normal,away or there's going to be total internal refraction?

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Its angle of incidence is too large for it to pass through that face.

Note that the refractive index itself, and hence the critical angle for blue, depends on the wavelength of blue light.

May I suggest that the term 'diffraction' in the title of the post be changed to 'refraction'.

The path taken by the emergent ray for blue light will depend on the angle at which the light enters the prism and the refractive index of the prism material. If the blue light enters the prism at an angle greater than the critical angle, it will undergo total internal reflection and travel along the boundary of the prism. If the angle of incidence is less than the critical angle, the blue light will be refracted towards the normal as it exits the prism. The exact path of the refracted blue light will also depend on the shape and thickness of the prism. It is important to note that the refractive index of a material is wavelength-dependent, so the path of the refracted blue light may differ from the path of the refracted red light due to their different wavelengths.

## What is diffraction of light on a prism?

Diffraction of light on a prism is a phenomenon in which light waves are bent or spread out as they pass through a prism. This is due to the different wavelengths of light being refracted at different angles, causing the colors of the visible spectrum to separate.

## Why do blue and red light diffract differently on a prism?

The reason why blue and red light diffract differently on a prism is because they have different wavelengths. Blue light has a shorter wavelength and is therefore diffracted at a greater angle, while red light has a longer wavelength and is diffracted at a smaller angle.

## What is the relationship between the angle of diffraction and the wavelength of light?

The angle of diffraction is directly proportional to the wavelength of light. This means that the shorter the wavelength, the greater the angle of diffraction, and vice versa.

## How does the material of the prism affect the diffraction of light?

The material of the prism can affect the diffraction of light in two ways. First, the density and refractive index of the material can impact the amount of diffraction. Second, the surface of the prism can cause additional diffraction due to imperfections or irregularities.

## Can diffraction of light on a prism be used for practical applications?

Yes, diffraction of light on a prism has several practical applications. One of the most well-known is in spectroscopy, where the separation of colors on a prism can be used to analyze the composition of a substance. Prisms are also used in optics, such as in cameras and telescopes, to manipulate and focus light.