What do you understand by the deviation produced by a prism? Why is it caused? State three factors on which the angle of deviation depends.

In a prism, the ray of light suffers refraction at two faces. The prism produces a deviation at the first surface and another deviation at the second surface. Thus a prism produces a deviation in the path of light.
The value of the angle of deviation (or the deviation produced by a prism) depends on the following four factors:
(a) the angle of incidence (i)
(b) the material of prism(i.e., on refractive index μ)
(c) the angle of prism (A)
(d) The colour or wavelength (λ) of light used.