PHYS 102-4M
Exam #3, Ch 22, 23, & 24
29 March 2006
Name___________________
Constants c= 3 × 10
8
m/s
____1) A light year is equivalent to: (B) a.
20,000 years b.
9.4
× 10
15
m c.
8.2
× 10
12 d.
3.14
× 10
7
m
s
____2) The wavelength of light with a frequency of 10
14
Hz is: B a.
3 × 10
8
m b.
3 µ m c.
30 nm d.
3000 seconds
____3) Which of these types of light has the longest wavelength? C a.
X-rays b.
Visible light c.
Radio waves d.
Infrared radiation
____4) Which of these is not part of the electromagnetic spectrum? C a.
X-rays b.
Radio waves c.
Gravity waves d.
Microwaves e.
Gamma rays
____5) Michelson measured the speed of light by employing a B a.
Graduate student b.
Rotating mirror c.
Shuttered lamp d.
Cesium atom e.
Moons of Jupiter
____6) Light is incident on a reflective surface at an angle of 25 ° . What is the angle of the reflected light? C a.
-25 ° b.
30 ° c.
25 ° d.
65 °

____7) You are six foot tall. What is the minimum height that a mirror can be so that you will see your entire body in the mirror? B a.
2 feet b.
3 feet c.
4 feet d.
6 feet
____8) A real image A a.
Has a positive image distance b.
Can not be projected on a screen c.
Can be created by a convex mirror d.
Has a negative image distance e.
Is created by a diverging lens
____9) You stand 3 feet in front of a plane mirror. How far behind the mirror is your image? B a.
2 feet b.
3 feet c.
4 feet d.
6 feet
____10) Which of these is an example of a convex mirror? C a.
Bathroom vanity mirror b.
Mirror in a reflecting telescope c.
Security/surveillance mirror in a convenience store d.
Shaving/magnifying mirror
____11) Spherical aberration is caused by A a.
Light incident at different parts on the mirror is focused at different focal points b.
The mirror’s outer edges have a higher index of refraction because the mirror is thicker there c.
Mirrors are not perfectly spherical d.
The mirror reflects light of different wavelengths differently so that they focus at different points

____12) The radius of curvature for a concave mirror is 2 meters. What is the focal length? D a.
2 meters b.
–1 meter c.
4 meters d.
1 meter
____13) An object is 0.5 meters in front of a concave mirror whose focal length is 0.25 meters. What is the magnification of the image? Is it upright or inverted? D a.
m=1, Upright b.
m=2, Upright c.
m=-0.5, Inverted d.
m=-1, Inverted e.
m=-2, Inverted
____14) In this figure, the observer outside the tank sees an image of the fish as shown here (i.e. the fish shown in this figure is the image and not the actual fish). The position of the fish is actually B a.
Above where the person sees it b.
Below where the person sees it c.
At the same position as where the person sees it d.
None of the above
____15) Which of these principles do fiber optic cables not employ? D a.
Refraction b.
Total internal reflection c.
Snell’s Law d.
Interference e.
Law of reflection
____16) The index of refraction for glass is 1.5. What is the speed of light in glass? A a.
2 × 10
8
m/s b.
3 × 10
8
m/s c.
4.5
× 10
8 d.
6 × 10
8
m/s
m/s

____17) A virtual image is created by a converging lens. Where is the object? B a.
At the focal point b.
Between the focal point and the lens c.
Between the focal point and radius of curvature d.
At the radius of curvature
____18) For a converging lens, the image distance is 50 cm and the object distance is 75 cm. What is the power of this lens? B a.
30 diopters b.
3.3 diopters c.
3 Watts d.
30 cm
____19) The particle nature of light is reflected by which of these phenomena? C a.
Single-slit diffraction b.
Constructive interference c.
Law of Reflection d.
Snell’s Law
____20) The color of light is directly dependent on which of these values? B a.
Intensity b.
Wavelength c.
Angle of reflection d.
The light’s speed
____21) For a double slit diffraction pattern, what is the difference in path lengths of the two rays for the first dark fringe? B a.
λ /4 b.
λ /2 c.
3 λ /2 d.
λ

____22) Two slits are separated by 3 mm. Light of wavelength 750 nm is incident upon the slit. The screen is 10 meters away. What is the distance between the central maximum (on the diffraction pattern) and the fourth bright fringe? A a.
0.01 m b.
1 mm c.
0.001 m d.
10 cm
____23) A diffraction grating has 4000 lines/cm. What is the wavelength of the light if a second order bright fringe is at an angle of 28 ° ? B a.
800 nm b.
590 nm c.
400 nm d.
370 nm
____24) Spectrometers generally use what device to disperse light into its different wavelengths? B a.
Prism b.
Diffraction grating c.
Rectangular glass slab d.
Circular disk
____25) Which of these is not a type of diffraction grating? B a.
Transmission grating b.
Refraction grating c.
Reflection grating d.
All of the above are types of diffraction gratings.

____26) A single slit has a width of 1 mm and is illuminated by light with λ=500 nm. A screen is 50 cm away from the slit. How far from the central maximum is the first dark spot? B a.
0.25 cm b.
0.025 cm c.
0.25 m d.
2.5 µm
____27) A diffraction grating is illuminated with light of λ=500 nm. The first order bright fringe is at an angle of 30
○
. What is the distance between adjacent slits on this grating? A a.
1 µm b.
1 cm c.
1 nm d.
0.01 m
____28) Unpolarized light with an intensity of 10 W/m that is at an angle of 20
○
2
is incident on a polarizing filter
with respect to the vertical axis. What is the intensity of the light after it passes through the filter? C a.
8.8 W/m
2 b.
10 W/m
2 c.
5 W/m
2 d.
4.4 W/m
2
____29) Light is in glass (n g
=1.5) and is incident at an air-glass interface at an angle θ as shown in this figure. What is the minimum angle θ such that the light will undergo total internal reflection? A a.
42
○ b.
55 c.
33
○
○ d.
90
○
Air
θ
Glass

____30) Light is in glass (n g
=1.5) and is incident at an air-glass interface at an angle
θ
1
=30
○
as shown in this figure. What is the angle θ
2
? (The lines are not drawn to scale.) C a.
60
○ b.
33
○ c.
49 d.
72
○
○
Air
θ
2
θ
1
Glass
____31) Light polarized in the y-direction has an intensity of 4 W/m
2
. It is incident on a polarizing filter at an angle of 60
○
with respect to the y-direction. What is the intensity of the light after passing through the filter? B a.
2 W/m
2 b.
1 W/m
2 c.
3 W/m
2 d.
3.5 W/m
2
____32) Which of these rays is drawn incorrectly for this mirror? A a.
A b.
B c.
C d.
All are correct e.
None are correct
A
B
●
F
C

____33) In Young’s double slit experiment, when you increase the width of the slit and keep the wavelength constant, what happens to the diffraction pattern? B a.
It spreads out b.
It shrinks together c.
It disappears d.
It stays the same
____34) Two waves are emitted from the same source (so they are in phase) and have a wavelength of 1 meter. One wave travels 2 meters and the other wave travels
2.5 meters before the two waves come together at a screen. At the point where they meet on the screen, what will you see? A a.
Dark fringe b.
Bright fringe c.
Ronald McDonald d.
Barney the Purple Dinosaur
____35) You are using test version B. Please bubble “B” on your scantron. B