An equilateral prism in air ( with an index of refraction as given in the accomp
ID: 1301682 • Letter: A
Question
An equilateral prism in air ( with an index of refraction as given in the accompanying table ) is illustrated. A ray of light iwth a wavelength ? = 540nm enters the prism at side 1 and is refracted. The angle the incident ray makes with the normal N is 42 (degree) . A table of refractive index n is shown for various wavelenths.
a) what is the refraction angle with respect to normal N of the ray inside the prism?
b) Will the refracted ray internal to the prism be totally internally reflected when encountering side 2 of the prism ?
c) If the prism were immersed in a fluid with n = 1.7, what would the refraction angle be for the incoming ray?
Explanation / Answer
A) na *sin(42) = nb*sin(thetab)...
thetab = sin^-1[(na/nb)*sin(42)]...
thetab = sin^-1[(1/1.7)*sin(42)]
theat b= 23.17 degrees...
B) critical angle is thetac = sin^-1(1/n) = sin^-1(1/1.7) = 36.03 degrees..
23.17 < 36.03 degrees...hence the light wil not get total internal reflected...
C) same as incident angle 42 degrees