For an equilateral triangular glass prism (A = 60°), the angle of minimum deviation is measured to be Dm = 30°. What is the refractive index μ of the prism material?
Answer and explanation
Correct answer: B. √2 ≈ 1.414
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and .
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and .
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- Step 1: The prism formula relating refracting angle , angle of minimum deviation , and refractive index is:
- Step 2: Substitute and :
- Step 3: Compute the sine values:
- Step 4: Calculate :
Answer
√2 ≈ 1.414
Why not the others: '1.500' is a typical textbook glass index assumed without calculating; '√3 ≈ 1.732' would result if ; '1.333' is the refractive index of water.
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