Question

When the angle of incidence is 60° on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is(a) √2 × 10⁸ ms⁻¹(b) √3 × 10⁸ ms⁻¹(c) 2 × 10⁸ ms⁻¹(d) 3 × 10⁸ ms⁻¹

Answer 1

option c is correct...

Answer 2

Answer:

B) √3 × 10⁸ ms⁻¹

Explanation:

Angle of incidence = 60°

Refractive index of glass, μg = tanθp

where θp is the polarising angle  

Thus,

μg = tan60° = √3

Now , μg = c/vg  

Therefore c/vg = √3

= vg =3× 10⁸/√3

= √3 × 10⁸ ms⁻¹

Thus, the velocity of light in glass is = √3 × 10⁸ ms⁻¹