Question

For 589 nm light, calculate the critical angle for the following materials surrounded by air.

(a) fused quartz
°
(b) gallium phosphide
°
(c) ice
°

Answer 1

a)
we know,
refractive indes of fused silica at 587 nm, n = 1.4584

critical angle, theta_c = sin^-1(1/n)

= sin^-1(1/1.4584)

= 43.3 degrees <<<<<<<<<<<<<---------Answer

b) for gallium phosphide, n = 3.31

critical angle, theta_c = sin^-1(1/n)

= sin^-1(1/3.31)

= 17.6 degrees <<<<<<<<<<<<<---------Answer

c) for ice, n = 1.309

critical angle, theta_c = sin^-1(1/n)

= sin^-1(1/1.309)

= 49.8 degrees <<<<<<<<<<<<<---------Answer