NEET2018Physics-Ray Optics
NEET 2018 Physics Prisms MCQ Question
Type: MCQ-conceptual-Hard-Class 12
The refractive index of the material of a prism is √2 and the angle of the prism is 30°. One of the two refracting surfaces 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
A
60°
B
45°
C
30°
D
zero
Correct Answer
Option C
Detailed Explanation
For the light to retrace its path, the angle of incidence should be equal to the angle of reflection. Using the prism formula and conditions for total internal reflection, the angle can be calculated.
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