Question

define the term angle of deviation

Answer 1

Hi.....

The angle of deviation through a triangular prism is defined as the angle between the incident ray and the emerging ray (angle δ). It can be shown that when the angle of incidence i is equal to the angle of refraction r' for the emerging ray, the angle of deviation is at a minimum.

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Answer 2

Word Origin. noun Optics. the angleequal to the difference between theangle of incidence and the angle of refraction of a ray of light passing through the surface between one medium and another of different refractive index.

or
the angle equal to the difference betweenthe angle of incidence and the angle ofrefraction ofa ray of light passing throughthe surface between one medium andanother of different refractive index.