Question

What should be the angle of incidence for a ray of light which suffers a minimum deviation of ${36}^{\circ }$​ through an equilateral prism?

• A. 90^o
• B. 28^o
• C. 36^o
• D. 48^o

Answer 1

The correct option is D

48^o

${\delta }_m$​ = ${36}^{\circ }$​, i = ? ∠ A = ${60}^{\circ }$​

${\delta }_m$​​ = 2i – A

2i = ${\delta }_m$​ + A

2i = ${36}^{\circ }$​ + ${60}^{\circ }$​​ = ${96}^{\circ }$​​

i = $\frac{{96}^{\circ }}{2}$ = ${48}^{\circ }$​​