Question

glass plate of refractive index 1.732 is to be used as a polariser its polarising angle is

Answer 1

Refractive index of glass plate , μ = 1.732 ≈ √3 { as you know, √3 ≈ 1.732 }
according to Brewster's law,
$\bold{\mu_P=tan\theta_P}$
Here $\bold{\mu_P}$ is refractive index of body which is used in polisher .
And $\bold{\theta_P}$ is the polarising angle .

so, polarising angle for glass plate = tan⁻¹(μ) = tan⁻¹(√3) = 60° [ ∵tan60° = √3]

Hence, answer is 60°