Question

A given ray of light suffers minimum deviation in an equilateral prism $P$. Additional prism $Q$ and $R$ of identical shape and of the same material as $P$ are now added as shown in the figure. The ray will now suffer

• A. greater deviation
• B. no deviation
• C. same deviation as before
• D. total internal reflection

Answer 1

Answer: (C)

There will be no refraction from $P$ to $Q$ and then from $Q$ to $R$ (all being identical). Hence the ray will now have the same deviation.