Explain the case of minimum angle deviationand how does it depend upon the angle of incidence and other angles?
Angle of deviation: The angle between the incident ray and the emergent ray is called angle of deviation.
For example: In a prism the angle of deviation is shown.
The required relation is, i + e = A + ?
i' is the angle of incidence
e is the angle of emergence
A is the angle of prism
? is the angle of deviation
? = i + e A
Thus, angle of deviation depends on i, e and A. Also the deviation depends on the refractive index of the material of the prism.
The Factors affecting the angle of deviation are:
1)Angle of Incidence .
As the angle of incidence increases , first the angle of deviation decreases and becomes minimum for a particular value of angle of incidence then again increases.
2)Angle of Prism.
For a given angle of incidence the angle of deviation increases with increase in the angle of Prism.
3)Refractive Index of the Prism material.
For a given angle of incidence , the angle of deviation increases with increase in the refractive index of the Prism material.
4)Wave length of Light.
For a given angle of incidence the angle of deviation decreases with in increase of wave length of light.