A prism, made of glass of refractive index 1.50, has two plane faces at an angle 33 to each other. A ray of light enters the glass from one side perpendicular to that face and emerges through the other.
Part A:
As the ray enters the glass, what is its angle of incidence ?
Give your answer in degrees.
PartB:
Just before the ray emerges from the glass, what is its angle of incidence ?
Give your answer in degrees.
Part C:
If the prism is in air calculate the deviation of the ray.
Give your answer in degrees. Remember, you're being asked for the deviation angle, not the angle of refraction. The deviation angle is the difference between the incidence and refraction angles at the glass/air interface.
2 answers
Learn Snell's law and make a serious attempt on your own. We are not going to do all of these for you.
A: an angle of incidence is zero because this is the angle between the normal to the surface and the incident ray.
B: examine the triangle formed by: the point where the ray enters the prism, the vertex of triangle (33o) and the point where the ray emerges from the prism. β = 180o - 90o - 33o=57o. This is the angle between the ray propagating in the prism and the second plane face of prism, therefore, the second angle of incidence is 33o.
C: sin r/sin i1=1.5, sin r = 1.5•sin i1=0.817,
r = 54.8o.
deviation is 57o-54.8o=2.2o
B: examine the triangle formed by: the point where the ray enters the prism, the vertex of triangle (33o) and the point where the ray emerges from the prism. β = 180o - 90o - 33o=57o. This is the angle between the ray propagating in the prism and the second plane face of prism, therefore, the second angle of incidence is 33o.
C: sin r/sin i1=1.5, sin r = 1.5•sin i1=0.817,
r = 54.8o.
deviation is 57o-54.8o=2.2o