Why the angle between the reflected rays at two surfaces of prism is twice the angle of the prism?
Answers
✔At this point the angle of incidence is called the critical angle. Any further increase in the angle of incidence will mean the ray is reflected , not refracted. When whitelight passes from air into a triangular prism , it is refracted as it enters, and then again as it exits.
There is an angle of incidence at which the sum of the two deflections is minimal. The deviation angle at this point is called the "minimum deviation" angle, or "angle of minimum deviation" At the minimum deviation angle, the incidence and exit angles of the ray are identical. One of the factors that causes a rainbow is the bunching of light rays at the minimum deviation angle that is close to the rainbow angle.
A convenient way to measure the refractive index of a prism is to direct a light ray through the prism such that it produces the minimum deviation angle.
The angle of minimum deviation is attained when the angle of incidence and angle of emergence for a ray of light