Question

An equilaterial prism is kept on a horizontal surface. A typical ray of light PQRS is shown in the figure. For minimum deviation

• A. the ray PQ must be horizontal.
• B. the ray RS must be horizontal.
• C. the ray QR must be horizontal.
• D. any one of them can be horizontal.

Answer 1

The correct option is C the ray QR must be horizontal.

During minimum deviation the ray inside the prism is parallel to the base of the prism in case of an equilateral prism.