A ray of light strikes the midpoint of one face of an equiangular (60°–60°–60°)

ID: 1436539 • Letter: A

Question

A ray of light strikes the midpoint of one face of an equiangular (60°–60°–60°) glass prism (n = 1.5) at an angle of incidence of 39.4°.

(a) Trace the path of the light ray through the glass, and find the angles of incidence and refraction at each surface.

1st surface:

incidence = °

refraction = °

2nd surface:

incidence = °

refraction = °

(b) If a small fraction of light is also reflected at each surface, find the angles of reflection at the surfaces.

reflection = ° (1st surface)

reflection = ° (2nd surface)

given refractive index of the prism = 1.5, angle of incidence = 39.4 degrees

from the definition refractive index = sin I /sin R

sin i - Sine angle of incidence
sin R - sine of angle or refraction

say angle of refraction at the first surface is x, then
sin 39.4/ sin x = 1.5 ==> x = 25.03 degrees

now the angle of incidence on the second surface is 60 -x.

   say y is the angle of refraction at the second surface is

   sin y / sin (60-x) = 1.5

sin y / sin (60-25.03) = 1.5 ===> y = 59.28 degrees

b) on the first surface the angle of incidence is equal to the angle of reflection which is 39.4 degrres

at teh second surface angle of reflection is 60-x = 60 -25.03 = 34.97 degrees

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.