Light travels from glass of refractive index 3 ÷ 2 into air. The light is incident at the Brewster angle for this glass-air interface. What is sin i(B)?
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Question

Light travels from glass of refractive index 3 ÷ 2 into air. The light is incident at the Brewster angle for this glass-air interface. What is sin i(B)?

G1 Physics · Accepted Answer

For light travelling from medium 1 to medium 2, tan i(B) = n₂ ÷ n₁. Here, n₁ = 3 ÷ 2, n₂ = 1. Therefore, tan i(B) = 1 ÷ (3 ÷ 2) = 2 ÷ 3. Construct a right triangle with opposite side 2 and adjacent side 3. The hypotenuse is √(2²+3²) = √13. Hence, sin i(B) = 2 ÷ √13. Correct option: A.