Questions

A ray of light traveling in medium 1 encounters an interface between medium 1 and medium 2. Part of the light is refracted into medium 2, and part is reflected back into medium 1.

If the refracted ray follows path D, not bending at all, what can you conclude?

  1. n1 = n2 (59/76) (78%)
  2. n2 > n1 (4/76) (5%)
  3. n1 > n2 (2/76) (3%)
  4. n1 > n2, and the angle of incidence in medium 1 is the critical angle for total internal reflection (4/76) (5%)
  5. n2 > n1, and the angle of incidence in medium 1 is the critical angle for total internal reflection (2/76) (3%)
  6. This is not actually possible (5/76) (7%)
















If the ray of light comes in at a non-zero angle and does not change direction then n1 = n2 (choice 1).

If the refracted ray follows path A, what can you conclude?

  1. n1 = n2
  2. n2 > n1
  3. n1 > n2
  4. n1 > n2, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  5. n2 > n1, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  6. This is not actually possible
















This would require a negative index of refraction. Let's assume that is not possible (choice 6)...the ray of light should always cross the normal.

If the refracted ray follows path C, what can you conclude?

  1. n1 = n2
  2. n2 > n1
  3. n1 > n2
  4. n1 > n2, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  5. n2 > n1, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  6. This is not actually possible
















Crossing the interface the ray of light bends toward the normal, so n2 > n1 (choice 2).

If the refracted ray follows path F, what can you conclude?

  1. n1 = n2
  2. n2 > n1
  3. n1 > n2
  4. n1 > n2, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  5. n2 > n1, and the angle of incidence in medium 1 is the critical angle for total internal reflection
  6. This is not actually possible
















First, the ray bends away from the normal, so n1 > n2. Second, when the angle in the second medium is 90° the angle of incidence is the critical angle. Choice 4 is correct.