A glass tank of refractive index 1.5 is filled with a liquid of refractive index μ. For every possible incidence angle of a ray entering the liquid, reflection at the liquid-glass interface is never completely polarized. Find the minimum μ.

Question

G1 Physics · Accepted Answer

For complete polarization at the liquid-glass interface, Brewster incidence must be attainable. At the limiting case the Brewster angle equals the maximum refraction angle in the liquid. Using tan i=1.5/μ and sin rₘₐₓ=1/μ gives μ=3/√5. Option A.