Conceptual Questions:
1. Which of the following describes what will happen to a light ray incident on an air-to-glass boundary?
a. total reflection
b. total transmission
c. partial reflection, partial transmission
d. depends on the angle of incidence
2. The 22-degree halo around the sun or moon is formed from
a. refraction in plate-like ice crystals.
b. refraction in pencil-like ice crystals.
c. refraction in water droplets.
d. reflection off ice crystals.
3. Rainbows may be visible
a. 22 degrees away from the sun.
b. 22 degrees away from the shadow of your head.
c. 42 degrees away from the shadow of your head.
d. 42 degrees away from the sun.
e. only in the morning or evening.
4. A line representing a wavefront for a wave should be drawn:
a. from the source to the receiver.
b. from one crest to the preceding crest.
c. along one of the crests of the wave.
d. in the direction the wave is moving.
5. When light from air hits a smooth piece of glass with the ray perpendicular to the glass surface, the part of the light passing into the glass
a. will not change its speed.
b. will not change its frequency.
c. will not change its wavelength.
d. will not change its intensity.
6. Dispersion occurs when:
a. some materials bend light more than other materials.
b. a material slows down some wavelengths more than others.
c. a material changes some frequencies more than others.
d. light has different speeds in different materials.
7. Which of the following describes what will happen to a light ray incident on an glass-to-air boundary at greater than the critical angle?
a. total reflection
b. total transmission
c. partial reflection, partial transmission
d. depends on the angle of incidence
8. A ray of white light, incident upon a glass prism, is dispersed as usual according to frequency. Which one of the following frequencies experiences the greatest angle of deviation?
a. Those perceived as orange.
b. Those perceived as violet.
c. Those perceived as red.
d. Those perceived as green.
Numerical Problems: answers link to a help page.
1. Water has an index of refraction of 1.333. What is the speed of light through it?
2. A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 25 deg from the normal. Find the angle of the refracted ray within the glass with respect to the normal.
3. A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 25 deg from the normal. Find the angle of the ray reflected off the glass surface with respect to the normal.
4. A monochromatic beam of light in air has a wavelength of 589 nm in air. It passes through glass (n = 1.52) and then through carbon disulfide (n = 1.63). What is its wavelength in the carbon disulfide?
5. A beam of light in air is incident on the surface of a rectangular block of clear plastic (n = 1.49) at an angle of 35 deg from the normal of the surface. The light beam passes through the block and re-emerges from the opposite side into air at what angle from the normal to that surface?
6. As the angle of incidence is increased for a ray incident on a reflecting surface, the angle between the incident and reflected rays ultimately approaches what value?
7. Diamond has an index of refraction of 2.419. What is the critical angle for internal reflection inside a diamond that is surrounded by air?
8. A fiber optic cable (n = 1.50) is submerged in water. What is the critical angle for light to stay inside the cable?
9. A certain kind of glass has index of refraction = 1.65 for bluish light and index of refraction = 1.61 for reddish light. If a beam of white light (containing all visible wavelengths) is incident at an angle of 30 deg, what is the angle between the reddish and bluish light inside the glass?