Unpolarised light is incident on a medium at an angle of incidence 60°. The reflected ray is perpendicular to the refracted ray. Refractive index (μ) of the medium is:

1.73

The correct answer is Option (2) → 1.73

According to Brewster's law,

$\tan θ_B=μ$

where,

$θ_B$ = Brewster Angle

$μ$ = Refractive index

$∴μ=\tan(90°-60°)$

$=\tan 30°$

$≃1.732$