Target Exam

CUET

Subject

Physics

Chapter

Ray Optics

Question:

For a glass prism ($μ = \sqrt{3}$), the angle of minimum deviation is equal to the angle of prism. What is the angle of prism?

Options:

$\frac{π}{6}$

$\frac{π}{4}$

$\frac{π}{3}$

$\frac{2π}{3}$

Correct Answer:

$\frac{π}{3}$

Explanation:

The correct answer is Option (3) → $\frac{π}{3}$

for a glass prism, the angle of minimum deviation -

$μ=\frac{\sin\left(\frac{A+δ_{min}}{2}\right)}{\sin\left(\frac{A}{2}\right)}$

Since, $δ_m=A$

$\sqrt{3}=\frac{\sin(A)}{\sin\left(\frac{A}{2}\right)}=2\cos\left(\frac{A}{2}\right)$

$⇒\cos\left(\frac{A}{2}\right)=\frac{\sqrt{3}}{2}$

$⇒A=30×2=60°$