Question

A light ray is incident on a rectangular glass slab at an angle of 60°. What is the angle between the ray coming out of the slab and the normal to the face of rectangular slab from which it comes out?

Answer 1

Ray of light strikes the mirror at an angle of 60°. 

⇒ It will make an angle of 300 (900 – 600) with the normal. 

∴ Angle of incidence = 300. 

Now, By laws of refraction; 

µ = \(\frac{Sin\,i}{Sin\,r}\)

Angle of incidence is 60° 

Refractive index of glass slab is 1.5 

Putting the value in the above equation, we get 

1.5 = \(\frac{0.866}{sin\,r}\)

On solving the above equation, we get 

sin r = \(\frac{0.866}{1.5}\)

Angle of refraction, r= 35.26° 

Thus the angel of refraction is 35.26° from the normal.