ame: ________________________
Exam 3--S12--PHYS102
30 April 2012
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of the following statements is true?
a.
____
____
Newton believed light was a particle
c. Young showed light was a particle
because of refraction.
through the double-slit experiment
b. Huygens believed light was a wave
d. Einstein showed light was a particle
because of reflection
through the photoelectric effect
2. These two mirrors sit at an angle of 120º to one another. A ray of light is incident at 50º on the first mirror.
What is the angle of reflection (θr), with respect to a perpendicular line to the second mirror, as shown?
a. 40°
b. 50°
c. 70°
3. Which of the following is true?
a.
b.
n1>n2
n1=n2
d.
e.
60°
20°
c.
d.
n1<n2
Not enough information
1
____
____
4. What is the speed of light in glass (n=1.5)?
a. 4.5×108 m/s
c. 0.5×108 m/s
8
d. 2×108 m/s
b. 3.0×10 m/s
5. A ray of light is in a medium as shown in this figure. What is the angle, θ, measured from the normal line,
that the ray of light emerges from the water?
a.
b.
28°
52°
c.
d.
2
33°
45°
____
____
____
____
6. Consider the light ray in an acrylic medium shown in this figure. What must be the angle θ1 for the ray to
undergo total internal reflection?
a. 0.71°
d. 46°
b. 0.0012°
e. Total internal reflection does not occur
c. 42°
7. Your eye consists of a convex lens that creates an image on your retina. You look at a very distant object,
and you eye lens has a particular focal length. In order to focus on a nearby object, how must the focal length
of your eye lens change?
a. the focal length increases
c. the focal length remains the same
b. the focal length decreases
8. Which of these appropriately lists the photons in order of energy, from the least energy to the greatest
energy?
a. x-rays, ultraviolet, radio, infrared
b. radio, infrared, ultraviolet, x-rays
9. Which of these rays is drawn incorrectly?
a.
b.
(a)
(b)
c.
d.
radio, ultraviolet, infrared, x-rays
infrared, radio, x-rays, ultraviolet
c.
d.
(c)
all are correct
3
____ 10. 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 give the camera a smaller field of view
b. to reduce the effects of spherical
d. to block flying monkeys from coming
aberration
into your camera
____ 11. The person in this figure is standing in front of a flat mirror. There is a star in front of the person as shown.
Where does the person see the image of the star?
a. (a)
b. (b)
c. (c)
____ 12. Which of these aberrations occur in mirrors:
d.
e.
(d)
(e)
c.
d.
I & III
II & III
I. spherical aberrations
II. geometric aberrations
III. chromatic aberrations
IV. diffraction aberrations
a.
b.
I & IV
I only
4
____ 13. Where is the image formed by the second lens in this figure?
a. 30 cm to the left of lens 2
c. 15 cm to the right of lens 2
b. 100 cm to the right of lens 2
d. there is no image
____ 14. You stand 100 cm in front of a mirror and find that your image is ½ your actual size. What is the focal length
of the mirror? (Hint: What kind of mirror is this? Is the magnification positive or negative?)
a. -25 cm
c. -100 cm
b. 50 cm
d. 33 cm
____ 15. You look in a mirror and see an image of your nose that is bigger than your actual nose. Which of these
options correctly give the type of mirror and describe the image?
a.
b.
convex mirror, virtual image, inverted
concave mirror, virtual image, upright
c.
d.
5
flat mirror, virtual image, upright
convex mirror, real image, inverted
____ 16. What can you do to see more of yourself in a flat mirror?
a. move towards the mirror
c. get a bigger mirror
b. move away from the mirror
____ 17. Interference occurs in what type of waves?
a. mechanical waves
c. light waves
b. sound waves
d. all of these
____ 18. Which statement best describes the phase of these 2 waves:
I. in-phase
1
II. out-of-phase by 2 λ
III. out-of-phase by 90û
IV. out-of-phase by 180 û
V. out-of-phase by 1 λ
a. II & IV
d. II & III
b. IV & V
e. I
c. II
____ 19. Two coherent waves have a wavelength of 4 m. The first wave travels a distance of 3 meters, and the second
wave travels a distance of 11 meters. Then, the two waves recombine. What type of interference occurs?
a. destructive
b. constructive
____ 20. A diffraction grating has 540 lines/mm. How far apart are two adjacent slits on the grating?
a.
b.
1.9×10−6 m
0.24 m
c.
d.
6
0.540 m
0.0032 m
____ 21. A laser beam (λ = 650 nm) is incident on two slits 0.100 mm apart. How far is the second bright fringe from
the central maxium on a screen 5 meters away?
a. 6.5 cm
c. 0.5 cm
b. 12 cm
d. 3.2 cm
____ 22. In a Young's double-slit interference apparatus, by what factor is the distance between adjacent light and dark
fringes changed when the separation between slits is doubled?
a. 1/4
c. 1/2
b. 2
d. 1
____ 23. After light from a source passes through two slits, a first order bright spot is seen on the wall at point P.
Which labeled distance is necessarily equal to the wavelength of the light?
a.
b.
(a)
(b)
c.
d.
7
(c)
(d)
____ 24. At what angle will the second order maximum occur for a wavelength of 400 nm using a diffraction grating
with 10000 lines per cm?
a.
b.
15.5°
53°
24°
No second order maximum will occur in
this case.
____ 25. 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. 1
b. 2
____ 26. This is version B. Choose B for this question
a. A
b. B
c.
d.
c.
d.
3
4
c.
d.
C
D
8
ID: A
Exam 3--S12--PHYS102
Answer Section
30 April 2012
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
D
C
A
D
D
D
B
B
B
B
C
B
D
C
B
C
D
A
B
A
A
C
A
B
B
B
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
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
DIF: 1
DIF: 2
1
TOP: 24.8 The Diffraction Grating