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Asked in GSEB Board July 2022 · Brewster's law and polarisation by reflection
Given: light passing from air into glass of refractive index μ = 1.5.
Idea: the Brewster angle is the angle of incidence at which the reflected light comes out completely polarised, and it obeys μ = tan i_B.
That form follows from the reflected and refracted rays being perpendicular at this angle: with r = 90° - i_B, Snell's law μ = (sin i_B)/(sin r) collapses to a tangent.
i_B = tan⁻¹(1.5).
i_B = 56.3°, which is the 57° offered.
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