Chapters 28
Reflection and Refraction
Topics
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Reflection
Law of Reflection
– plane mirrors
– diffuse reflection
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Refraction
– Mirage
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Cause of Refraction
– dispersion
– rainbows
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Total internal Reflection
Lenses
– images formed by lenses
– lens defects
Reflection - Mechanism
Reflection
Mirror Images
Curved Mirror Images
Diffuse Reflection
Refraction
Cause of Refraction
Snell’s Law
n1sinq1 = n2sinq2
where n = c/v
Refraction through a Prism or Lens
Examples of Refraction
Where’s the Fish?
Dispersion
Dispersion by a Raindrop
Dispersion by a Raindrop
Total Internal Reflection
Total Internal Reflection
Lenses
Lenses
Magnification
Magnification
Lens Defects
Spherical Aberration
Chromatic Aberration
Clicker Questions
1. Object and image for a plane mirror lie
A) at right angles to each other.
B) equal distances from the mirror.
C) along the same plane.
D) all of these
E) none of these
2. When light reflects from a surface, there is a change in its
A) speed.
B) wavelength.
C) frequency.
D) all of these
E) none of these
3. If you walk towards a mirror at a certain speed, the relative speed
between you and your image is
A) twice your speed.
B) half your speed.
C) your speed.
D) none of these
Clicker Questions
4. It is difficult to see the roadway in front of you when you are driving on a rainy
night mainly because
A) the film of water on the roadway makes the road less diffuse.
B) light scatters from raindrops and cuts down the light to reach your eyes.
C) the film of water on your windshield provides an additional reflecting surface.
D) of added condensation on the inner surface of the windshield.
E) none of these
5. When a mirror with a fixed beam on it is rotated through a certain angle, the
reflected beam is rotated through an angle that is
A) four times as large.
B) twice as large.
C) equal to the angle of rotation.
D) none of these
6. As a light ray enters or exits a water-air interface at an angle of 15 degrees
with the normal, it
A) always bends toward the normal.
B) always bends away from the normal.
C) does not bend.
D) sometimes bends towards the normal.
Clicker Questions
7. A mirage is a result of atmospheric
A) refraction.
aberrations.
B) dispersion.
C) scattering.
D) reflection.
8. Refraction results from differences in light's
A) speed.
B) frequency.
C) incident angles.
D) all of these
E) none of these
9. Light refracts when traveling from air into glass because light
A) has greater intensity in air than in glass.
B) travels slower in glass than in air.
C) has greater frequency in air than in glass.
D) has greater frequency in glass than in air.
E) has greater intensity in glass than in air.
E)
Clicker Questions
10. Different colors are dispersed by a prism because different colors in the
prism have different
A) directions.
B) energies.
C) speeds.
D) frequencies.
E) none of these
11. The image in a pinhole camera is
A) always right-side up.
B) sometimes inverted.
C) always inverted.
12. If you wish to spear a fish with a regular spear, you should compensate
for refraction between the air and water and throw your spear
A) below the sighted fish.
B) directly at the sighted fish.
C) above the sighted fish.