A certain prism is found to produce a minimum deviation of  38∘. It produces a deviation of  44° when the angle of incidence is either  42° or 62° . What will be the angle of incidence when it undergoes minimum deviation?

1. Given Minimum deviation  δm=38∘Angle of Incidence  i1=42∘ or 62∘Deviation  δ=44∘δ=i1+i2−A2. Here i1=42∘  and   i2=62∘44∘=42∘+62∘ −AA=60∘Using the formula for minimum deviation, we get⇒δm=2i−A⇒i=δm+A2⇒i=38+602∴i=49∘Therefore, the correct answer is (C).