Question

(b) The value of critical angle is 30° for total internal
reflection from any medium to vacuum; the speed of light
in that medium.​

Answer 1

Answer:

for critical angle the value of r becomes 90 degree n1 / n2 = sin 90 / sin 30 = 2 also n1/n2 = v2/v1 ... In the medium, "speed of light" is 1.5 \times 10^8 \ m/s. Explanation:. 

Answer 2

Answer:

For critical angle the value of r becomes 90 degree

n1 / n2 = sin 90 / sin 30 = 2

also,

n1/n2 = v2/v1

In the medium, "speed of light" is 1.5 \times 10^8 \ m/s.