If the refractive index of the material of a prism is $\cot \frac{A}{2}$, where A is the angle of prism then the angle of minimum deviation will be
(A) $\pi – 2A$
(B) $\frac{\pi}{2} – 2A$
(C) $\pi – A$
(D) $\frac{\pi}{2} – A$
Solution:
This question was asked in JEE-Mains 2024 on January 27, 2024 in the morning session.
Required Utensils:
- Equation of Prism from NCERT
![Equation of prism from NCERT](https://physicscookbook.com/wp-content/uploads/2024/03/image-1.png)
Preparation:
Given:
Refractive Index $= n = \cot \frac{A}{2} = \frac{\sin \frac{(A+D_m)}{2}}{\sin \frac{A}{2}}$
So, $\frac{\cos \frac{A}{2}}{\sin \frac{A}{2}} = \frac{\sin \frac{(A+D_m)}{2}}{\sin \frac{A}{2}}$
Or, $\cos \frac{A}{2} = \sin \frac{(A+D_m)}{2}$
Or, $\frac{(A+D_m)}{2} = \frac{\pi}{2} – \frac{A}{2}$
Or $D_m = \pi – 2A$
Hence option (A) is the correct answer
Resources:
- Refraction by a Prism
- Solution on toppr.com
- Video Solution
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