Question

Angle of deviation is between:
(A) Real and virtual image
(B) Incident and emergent ray
(C) Plane of reflection and plane of incidence
(D) None of the above

Answer 1

Hint : In this question, we are required to find the position of angle of deviation, and in order to find that we will consider a prism in which we will pass an incident ray and we will get refracted ray and emerging ray. Then through observation, we will get the angle of deviation.

Complete step by step answer:
Definition of Angle of deviation: The angle which the emergent ray makes with the direction of the incident ray, When a ray passes from one medium to another medium it creates an angle between the direction of refracted ray and the direction of the incident ray.
In other words, we can say that angle of deviation is the angle of deviation 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 traveling from one medium to another that has a different refractive index.
Example: A plane wavefront is incident at an angle of ${40}^o$ on the surface of the glass. Calculate the angle of deviation if the angle of refraction is${15}^o$.
$\Rightarrow$Angle of incidence, $i={40}^o$
Angle of refraction, $r={15}^o$
Angle of deviation, $\delta =i-r={40}^o-{15}^o={25}^{{}^o}$
Diagram:

The angle of deviation of the prism depends on the following factors:
(A) Angle of prism
(B) Angle of incidence
(C) Wavelength of the light
(D) Refractive index of the optical material, that is prism.
So the angle of deviation is between the incident and emergent ray. Hence option B. is correct.

Note: In order to solve this kind of question, we should have knowledge about ray optics and its principle. To better understand the angle of deviation, we can observe the diagram shown above in the solution.