## Mastering Physics Solutions: Is Light Reflected or Refracted?

Is Light Reflected or Refracted?

Part A = Increases
Part B = +1
Part C = θ2 > θ1
Part D = θ2 < θ1
Part E = Just pick the material with the greatest index of refraction
Part F = Increases up to a maximum value of 90 degrees.

Solution Below:

Part A

When light propagates from a material with a given index of refraction into a material with a smaller index of refraction, the speed of light

Increases

Part B

What is the minimum value that the index of refraction can have?

+1

Part C

Now consider a ray of light that propagates from water (n = 1.33) to air (n = 1). If the incident ray strikes the water-air interface at an angle θ1 ≠ 0, which of the following relations regarding the angle of refraction, θ2, is correct?

θ2 > θ1

θ2 > θ1

Part D

Consider a ray of light that propagates from water (n = 1.33) to glass (n = 1.52). If the incident ray strikes the water-glass interface at an angle θ1 ≠ 0, which of the following relations regarding the angle of refraction, θ2, is correct?

θ2 < θ1

θ2 < θ1

Part E

Consider a ray of light that propagates from air (n = 1) to any one of the materials listed below. Assuming that the ray strikes the interface with any of the listed materials always at the same angle θ1, in which material will the direction of propagation of the ray change the most due to refraction?

Just pick the material with the greatest index of refraction

Just pick the material with the greatest index of refraction

Part F

In the case of n1 > n2, if the incidence angle is increased, the angle of refraction

Increases up to a maximum value of 90 degrees.

Increases up to a maximum value of 90 degrees.

Part G

What is the critical angle θcrit for light propagating from a material with an index of refraction of 1.50 to a material with an index of refraction of 1.00?

The critical angle is the angle at which the angle of refraction equals 90 degrees. Use Snell’s law:

nsin(θ1) = nsin(θ2)
1.50 * sin(θcrit) = 1.00sin(90)
1.50 * sin(θcrit) = 1.00sin(90)
1.50 * sin(θcrit) = 1.00
sin(θcrit) = 0.667