A prism has a refracting angle of 60°. When placed in the position of minimum deviation, it produces a deviation of 30°. The angle of incidence is

Question

A prism has a refracting angle of 60°. When placed in the position of minimum deviation, it produces a deviation of 30°. The angle of incidence is (A) 30° (B) 45° (C) 15° (D) 60°

Tardigrade Admin · Accepted Answer

μ=( sin i/ sin r)=( sin ((δ +A/2))/ sin (A / 2)) r=A / 2 ( sin (i)/ sin (A / 2))=( sin ((δ +A/2))/ sin (A / 2)) i=(δ+A) / 2 =(30+60/2) =45°

Q. A prism has a refracting angle of $6 0^{\circ}$ . When placed in the position of minimum deviation, it produces a deviation of $3 0^{\circ}$ . The angle of incidence is

$3 0^{\circ}$

$4 5^{\circ}$

$1 5^{\circ}$

$6 0^{\circ}$

$μ = \frac{s i n i}{s i n r} = \frac{s i n ( \frac{δ + A}{2} )}{s i n ( A /2 )}$
$r = A /2$
$\frac{s i n ( i )}{s i n ( A /2 )} = \frac{s i n ( \frac{δ + A}{2} )}{s i n ( A /2 )}$
$i = (δ + A) /2$
$= \frac{30 + 60}{2}$
$= 4 5^{\circ}$

Q. A prism has a refracting angle of 60∘. When placed in the position of minimum deviation, it produces a deviation of 30∘. The angle of incidence is

30∘

45∘

15∘

60∘