Question

When an equilateral glass prism is in minimum deviation position,
(A) the refracted ray is parallel to the base of the prism.
(B) the angle of incidence is equal to the angle of emergence.

Choose the correct option.

• A. Only A is true
• B. Only B is true
• C. Both A and B are true
• D. Both A and B are false

Answer 1

Answer: (C)

Both A and B are true

Deviation, measured in degrees, is the angle an incident ray is turned through after passing through a prism. This deviation is a minimum for a prism when the path of a light ray is symmetrical about its axis of symmetry.