Question

When light rays are incident on a prism at an angle of 45⁰, the minimum deviation is obtained. If refractive index of the material of prism is $\sqrt { 2 }$, then the angle of prism will be

• A. 30⁰
• B. 40⁰
• C. 50⁰
• D. 60⁰

Answer 1

Answer: (D)

60⁰

Answer 2

$\Rightarrow$ $\Rightarrow$ $\sin \frac { A } { 2 } = \frac { \frac { 1 } { \sqrt { 2 } } } { \sqrt { 2 } } = \frac { 1 } { 2 }$ $\Rightarrow \frac { A } { 2 } = 30 ^ { \circ } \Rightarrow A = 60 ^ { \circ }$