There is a prism of refractive index equal to √2 and refracting angle equal to 30°. One of the two refracting surfaces of the prism is polished. A beam of monochromatic light entering into it strikes the silvered surface normally. The angle of incidence on the first surface is:
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Question

There is a prism of refractive index equal to √2 and refracting angle equal to 30°. One of the two refracting surfaces of the prism is polished. A beam of monochromatic light entering into it strikes the silvered surface normally. The angle of incidence on the first surface is:

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G1 Physics · Accepted Answer

Step 1: For perpendicular incidence at the silvered surface, the internal ray is normal to that face. Step 2: The refracted angle at the first face equals prism angle A = 30°. Step 3: Snell’s law sin i = √2 sin30° = 1/√2. Final answer: (C) i = 45°.