The angle of incidence on the surface of a diamond of refractive index 2.4, if the angle between the reflected and refracted rays is 90° is

Q.The angle of incidence on the surface of a diamond of refractive index 2.4, if the angle between the reflected and refracted rays is 90° is
(a) tan^-1(2.4)
(b) sin^-1(1/2.4)
(c) tan^-1 (1/2.4)
(d) cos^-1 (1/2.4)
Ans: A

Sol: According to question , i+r=90°  ….(i)

Applying Snell’s Law

1×sini = 2.4×sinr

sini = 2.4×sin(90-i) = 2.4cosi from(i)

tani = 2.4

i = tan⁻¹(2.4)