ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2023

The refractive index of the material of a prism is \( \sqrt{2} \) and angle of prism is \( 30^{\circ} \). One of the two refracting surface of the prism is made a mirror inwards, by silver coating at outer surface. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is:

  1. A \( 30^{\circ} \)
  2. B \( 45^{\circ} \)
  3. C \( 60^{\circ} \)
  4. D zero
Verified Solution

Answer & Solution

Correct Answer

(B) \( 45^{\circ} \)

Step-by-step Solution

Detailed explanation

For retrace path: \( r_2 = 0^{\circ} \) \( A = r_1 + r_2 \implies 30^{\circ} = r_1 + 0^{\circ} \implies r_1 = 30^{\circ} \) \( \sin(i_1) = \mu \sin(r_1) \) \( \sin(i_1) = \sqrt{2} \sin(30^{\circ}) \) \( \sin(i_1) = \sqrt{2} \cdot \frac{1}{2} = \frac{1}{\sqrt{2}} \)…
Same subject
Explore more questions on app
From CUET
Explore more questions on app