Name: ________________________ Class: ___________________ Date: __________
ID: A
Exam 4
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
1. You want a mirror to use as a security mirror in your store. Which of these is the best mirror to use?
a. Concave
c. Convex
b. Flat
d. Either Concave or Flat
2. Which of these aberrations occur in mirrors:
I. spherical aberrations
II. geometric aberrations
III. chromatic aberrations
IV. diffraction aberrations
____
____
a. I & IV
c. I & III
b. II & III
d. I only
3. This figure shows an object and the image of that object which is created by a particular type of mirror. If
the mirror is located as shown, what type of mirror will create this image?
a. Flat
c. Concave
b. Convex
d. Not enough information
4. A camera can be modeled as a simple converging lens that focuses an image on the film, which acts as a
screen. A camera is initially focused on a object just outside the focal length of the lens. If the photographer
then wants to focus on an object very far away, the lens must be:
a.
b.
moved away from the film
left where it is
c.
d.
1
moved toward the film
Not enough information
Name: ________________________
____
____
ID: A
5. This figure shows two people observing the image of a rock in a flat mirror. Person number 1 sees the image
of the rock at position C. Where does person #2 see the image of the rock?
a. A
b. B
c. C
6. What type of lens is this:
a.
b.
bi-concave
plano-convex
d.
e.
D
E
c.
d.
convex-concave
plano-concave
2
Name: ________________________
____
____
____
ID: A
7. This figure shows two lenses and an object. What is the magnification of the final image (i.e. after the
second lens)?
a. 1/2
c. -2
b. 1.0
d. -1/4
8. A convex spherical mirror has a radius of curvature of 20 cm. What is the image distance for an object that is
10 centimeters from the mirror?
a. 0 cm
d. -5 cm
b. -20 cm
e. there is no image
c. 20 cm
9. An object that is 4 cm high is placed 3 cm in front of a concave mirror. If the image is 8 cm high and virtual,
what is the focal length of the mirror?
a.
b.
6 cm
1.5 cm
c.
d.
3
12 cm
Not enough information
Name: ________________________
ID: A
____ 10. A converging lens has a focal length of 20 cm. What type of image does it form of an object placed at 10 cm
from the lens?
a. virtual
c. no image
b. real
d. not enough information
____ 11. A person uses a converging lens that has a focal length of 10 cm to inspect a gem. The lens forms a virtual
image 20 cm away. What is the magnitude of the magnification?
a. 1.5
c. 3
b. 2
d. 1/2
____ 12. If the Earth’s atmosphere no longer existed, how would the time of sunset be affected?
a. Sunset would occur earlier
c. Sunset would occur later
b. Sunset time would not change
d. No way to tell
____ 13. What can you do to see more of yourself in a flat mirror?
a. move away from the mirror
c. get a bigger mirror
b. move towards the mirror
____ 14. Most cameras have an aperture to block the outer edges of the lens. What is the purpose of this aperture?
a. to eliminate chromatic aberration
c. to reduce the effects of spherical
aberration
b. to give the camera a smaller field of view d. to block flying monkeys from coming
into your camera
____ 15. Two light sources emit waves of λ = 2 m which are in phase. The two waves from these sources meet at a
distant point. Wave 1 traveled 2 m to reach the point, and wave 2 traveled 3 m. When the waves meet, they
are
c. out of phase by 180°
a. out of phase but not by 180°
b. in phase
d. None of these
____ 16. In a double slit experiment, when the separation of the slits is decreased, how must the wavelength be
changed to maintain the same diffraction pattern on a screen 2 meters away?
a. wavelength stays the same
c. wavelength increased
b. wavelength decreased
d. Need to know the angle to tell
____ 17. Light of 500 nm is incident on a double slit of width 1000 nm. What is the highest order present in the
diffraction pattern?
a.
b.
1
2
c.
d.
4
3
4
Name: ________________________
ID: A
____ 18. In a double-slit experiment, what path difference have the two waves traveled to give the minimum at the
point given by the arrow in this figure?
1
λ
d. 2λ
2
b. 1λ
e. No path difference
1
c. 1 λ
2
____ 19. In a single slit diffraction pattern, what would you do to make the central bright spot narrower?
a.
a. move the screen further away
c. increase the wavelength
b. increase the slit width
d. decrease the slit width
____ 20. A Helium-Neon LASER beam (λ = 632.8 nm) is incident on two slits 1 mm apart. How wide is the central
maximum on a screen 8 m away from the double slit?
a.
b.
10 mm
5 mm
c.
d.
5
2.5 mm
8 mm
Name: ________________________
ID: A
____ 21. This figure shows two radio antennas, which are separated by 300 m. The antennas are emitting signals
(identical in both wavelength and phase) simultaneously. A car is traveling north as shown in the figure.
The car is at the second minimum of the interference pattern created by the two signals. What is the
wavelength of the light?
a. 45 m
c. 56 m
b. 632.8 nm
d. 74 m
____ 22. Red light of wavelength λ is incident on a single slit of width a, which forms a diffraction pattern on the
screen. If you use violet light, which has wavelength λ/4, what must the slit width be in order to keep the
diffraction pattern the same?
a. 2a
c.
4a
b. a/4
d. 4a
____ 23. A diffraction grating has 5000 lines/cm. What is the slit separation?
a. 300 nm
b. 2.0 µm
c. 250 nm
d. 2.5 µm
6
Name: ________________________
ID: A
____ 24. These 2 waves are:
a. 90° out of phase
c. in phase
d. 180° out of phase
b. 45° out of phase
____ 25. What caused the diffraction pattern in this picture?
a.
a laserbeam incident on a single slit
c.
b.
light from a light bulb incident on a
double slit
none of these
light incident on a circular object (such
d.
as a penny)
____ 26. Which of these is not a criteria that 2 light sources must fulfill in order to be able to create a diffraction
pattern?
a. same wavelength
d. constant phase
b. constant refraction
e. all of these are criteria
c. coherent
7
Name: ________________________
ID: A
____ 27. A discrete spectral line is seen at an angle of 30 ° in the third order spectrum of a diffraction grating
spectrometer. If the grating has 4000 lines/cm, what is the wavelength of the spectral line?
a. 325 nm
b. 417 nm
____ 28. Bubble A for this answer.
a. A
b. B
c.
d.
4.17×10-5 m
125 nm
c.
d.
C
D
8
ID: A
Exam 4
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
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27.
28.
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ANS:
C
D
B
C
C
B
A
D
A
A
C
A
C
C
C
B
B
C
B
B
D
B
B
D
B
B
B
A
PTS:
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PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
DIF: 2
1
TOP: 24.8 The Diffraction Grating