Question

An equilateral prism is placed on a horizontal surface. A ray PQ is incident onto it.For minimum deviation

• A. PQ is horizontal
• B. QR is horizontal
• C. RS is horizontal
• D. Any one will be horizontal

Answer 1

The correct option is B QR is horizontal

For minimum deviation is Angle of incidence is equal to angle of emergenge.

So as to satisfy the above condition its quite obvious that the ray to travel parallel to ground.

=. QR is parallel to horizontal

Hence obtion (B) is correct.