The exit surface of a prism with refractive index is coated with a material having refractive index . When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is _________. [2026

Question

The exit surface of a prism with refractive index $n$ is coated with a material having refractive index $\frac{n}{2}$ . When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is _________. [2026]

Smart Achievers · Accepted Answer

(3)

$i = e & r = \frac{A}{2} for minimum deviation$

$\sin r = \sin θ_{c}$

$\sin r = \frac{n / 2}{n}$

$\sin r = \frac{1}{2}$

$\sin \frac{A}{2} = \sin 30 °$

$\frac{A}{2} = 30 °$

$A = 60 °$

Solution

Q.
The exit surface of a prism with refractive index $n$ is coated with a material having refractive index $\frac{n}{2}$ . When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is _________. [2026]

1 $30 °$

2 $15 °$

3 $60 °$

4 $45 °$

Ans.
(3)

$i = e & r = \frac{A}{2} for minimum deviation$

$\sin r = \sin θ_{c}$

$\sin r = \frac{n / 2}{n}$

$\sin r = \frac{1}{2}$

$\sin \frac{A}{2} = \sin 30 °$

$\frac{A}{2} = 30 °$

$A = 60 °$

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Solution

Q. The exit surface of a prism with refractive index n is coated with a material having refractive index n2. When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is _________. [2026]

1 30°

2 15°

3 60°

4 45°

Ans. (3) i=e & r=A2 for minimum deviation sinr=sinθc sinr=n/2n sinr=12 sinA2=sin30° A2=30° A=60°