by principle of reversibility, the beam will return its path when it strikes the mirror perpendicularly
r2=0,r1=A=30o
∴r1+r2=A in a prism
Applying Snell's law at P sini=2sin30o=2×21=21
∠i=45o
The refractive index of the materiel of a prism is √2 and the angle of the prism is 30^o. One of the two refracting surface of the prism is made a…
NEET UG 2018 — Physics Optics
2018mcqmedium
The refractive index of the materiel of a prism is 2 and the angle of the prism is 30o. One of the two refracting surface of the prism is made a mirror inwards, by silver coating. 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
Official previous-year question
Held on 30 Apr 2018 · Verified 9 Jul 2026.
Options
- A
30o
- B
45o
- C
60o
- D
Zero
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