: the dihedral angle (as of a prism) included between the planes of the two sides through which the refracted beam passes — compare refraction angle.

As light passes through a prism, it is bent, or refracted, by the angles and plane faces of the prism and each wavelength of light is refracted by a slightly different amount. As a result, all of the colors in the white light of the sun separate into the individual bands of color characteristic of a rainbow.

Since different colors of light travel at different speeds, the refractive index is different for each color. As a result, when white light passes through the refracting surface of the prism, its components bend into different angles, causing the single beam of light to separate.

The Angle of deviation in a prism depends upon: Refractive index of the prism – The larger the refractive index, the larger the angle of deviation. Angle of the prism (i.e. Angle A in the figure) – The larger the prism angle, the larger the deviation angle.

In minimum deviation, the refracted ray in the prism is parallel to its base. In other words, the light ray is symmetrical about the axis of symmetry of the prism. Also, the angles of refractions are equal i.e. r1 = r2. And, the angle of incidence and angle of emergence equal each other (i = e).

Angle of Deviation Definition: The angle of deviation is defined as the angle which is obtained from the difference between the angle of incidence and the angle of refraction created by the ray of light travelling from one medium to another that has a different refractive index.

red

(i) Violet colour will deviate the most and (ii) red colour will deviate the least.

In visible light, violet light is deviated the most and red light is deviated the least because in glass the speed of violet light is the least and that of red light is the most.

The colour which is deviated the least is Red. Explanation: Violet has a shorter wavelength and deviates the most whereas red deviates the least…

Violet light has the maximum refractive index and least speed when travelling through a medium since it has the shortest wavelength. Thus, it bends most upon incidence and has maximum deviation.

Violet light

The refractive index (n) of a medium if the speed of light through the medium (v) is known. The speed of light in a medium (v) if its refractive index (n) is known….An overview of refraction and wavelength.

Red light

This implies that vacuum has a refractive index of 1, and that the frequency (f = v/λ) of the wave is not affected by the refractive index. As a result, the perceived color of the refracted light to a human eye which depends on the frequency is not affected by the refraction or the refractive index of the medium.