Question

A ray of light is incidenton surfaceof a medium at an angle 45° and is refracted in the medium at an angle 30° what is velocity of light in medium​

Answer 1

In the above mentioned question we have,

Angle of incidence (i)=45° and the angle of refraction (r)= 30°

Let us assume the the angle of incidence as sin i and the angle of reflection as sin r.

Refractive index (n) = sin i/ sin r= v1/v2

[Here v1 is velocity (speed) in the air and v2 is the velocity(speed) in the second medium.]

Now, equating the values known on the formula known we get,

Sin 45°/Sin 30°= 3×10^8 m/s/v2

v2=3×10^8×sin 30°/sin 45°

v2=3×10^8×1/2/1/√2[°•°sin30°=1/2&sin45°=1/

√2]

v2=2.12×10^8 m/s.

Therefore,the velocity of the light in the medium will be 2.12 m/s.