Question

A ray of light travelling in air is incident on the surface of a plastic slab at an angle if the angle of refraction is 30 and the refractive index of the plastic is root 3 find the angle of incidence

Answer 1

Hey there !

We know that Refractive Index is the ratio if sines of angle of incidence to angle of refraction. That is,

Refractive Index = Sin i / Sin r

So given that, Refractive Index is √3 and sin r is 30°

=> √3 = Sin i / Sin 30

=> √3 * Sin 30 = Sin i

=> √3 * 1 / 2 = Sin i

=> Sin i = √3 / 2

We know that, Sin 60 is √3 / 2. Hence,

Sin i = Sin 60

=> i = 60°

Hence the angle of incidence is 60°.

Hope my answer helped !

Answer 2

Answer:

60°

Explanation:

since we know that refractive index =sin i/sin r.

√3=sin i/sin 30°. (given that refractive

√3×sin 30°=sin i. index=√3,sin r=

√3×1/2=sin i. sin 60°)

sin i=√3/2.

so, sin i=60°. (√3/2= sin 60°)

Hence the angle of incident is 60°.