Question

ek samabahu prizm ekpristho rasmi ki apatan kon 30°.. another pritho ki patisarn kon 40°..so rasmi ki chuti kitni hogi ?
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Answer 1

Answer:

The incidence angle is 48.59 degrees and angle of minimum deviation is 36.98 degrees.

Explanation:

Refracting angle o f a prism A=60∘ and its refractive index is n=3/2. What is angle of incidence i to get minimum deviation. Also, find the minimum deviation. Assume the surrounding medium to be air (n=1).

We have,

Angle of prism, A = 60

Refractive index, n = 3/2

For minimum deviation, the refractive index is given by :

n=\dfrac{\sin (A+\delta _m)/2}{\sin A/2}n=

sinA/2

sin(A+δ

m

)/2

\delta_mδ

m

is minimum deviation

$$\begin{lgathered}\dfrac{3}{2}=\dfrac{\sin (60+\delta _m)/2}{\sin 60/2}\\\\\dfrac{3}{2}=\dfrac{\sin (60+\delta _m)/2}{\sin (30)}\\\\\dfrac{3}{4}=\sin(\dfrac{60+\delta _m}{2})\\\\\sin^{-1}(\dfrac{3}{4})=\dfrac{60+\delta _m}{2}\ ........(1)\\\\48.49=\dfrac{60+\delta _m}{2}\\\\\delta_m=36.98^{\circ}\end{lgathered}$$

We know that, angle of incidence is :

$$i=\dfrac{A+\delta_m}{2}$$