In vacuum, to travel distance d, light takes time t and in medium to travel distance 5d, it takes time T. The critical angle of the medium is

Options

(a) sin⁻¹(5T/t)
(b) sin⁻¹(5t/3T)
(c) sin⁻¹(5t/T)
(d) sin⁻¹(3t/5T)

Correct Answer:

sin⁻¹(5t/T)

Explanation:

In vacuum, c = d / t

In medium, v = 5d / T

As refractive index , μ = c / v = (d/t) / (5d/T) = T / 5t

Also, sin C = 1 / μ [If C is critical angle]

Therefore, C = sin⁻¹ [5t / T]