Exam form A
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Suppose you place your face in front of a converging mirror (i.e. one with positive radius of curvature)
A) Your image will be diminished in size.
B) No matter where you place yourself, a real image will be formed.
C) If you position yourself between the center of curvature and the focal point of the mirror, you will not
be able to see your image.
D) Your image will always be inverted.
E) None of these is true.
Situation 35.4
An erect object is 50 cm from a concave mirror of radius 60 cm.
2) In Situation 35.4, the character of the image is:
A) virtual and inverted
B) real and erect
C) indeterminate
D) real and inverted
E) virtual and erect
3) In Situation 35.4, the distance of the image from the mirror, in cm, is closest to:
A) 60
B) 19
C) 120
D) 35
E) 75
4) When an object is placed 30 cm from a converging lens, the image formed is positioned 60 cm from the
lens. If the object is moved 5 cm closer to the lens, the position of the image changes by 40 cm. What is the
focal length of the lens?
A) 20 cm
B) 16 cm
C) 25 cm
D) 32 cm
E) 36 cm
Figure 35.3
5) In Figure 35.3, a convex lens of focal length +150 cm is 90 cm to the right of a concave lens. A point source
of light is at P, 72 cm to the left of the concave lens. This point source produces a parallel beam to the right
of the convex lens. The focal length of the concave lens, in cm, is closest to:
A) -100
B) -43
C) -360
D) -33
E) -60
6) An optical engineer needs to ensure that the bright fringes from a double-slit are 15.7 mm apart on a
detector that is 1.37 m from the slits. If the slits are illuminated with 633-nm light, how far apart should the
slits be?
A) 64.0 mm
B) 59.6 mm
C) 55.2 mm
D) 50.8 mm
7) How many grating grooves are needed to resolve two spectral lines at l = 475 nm separated by 0.48 nm in
order m = 3?
A) 660 grooves
B) 330 grooves
C) 0 grooves
D) 990 grooves
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8) Find the minimum thickness of a soap film (n = 1.33) in which 660 nm light will undergo constructive
interference.
A) 124 nm
B) 248 nm
C) 217 nm
D) 186 nm
9) In a 35 mm single lens reflex camera (SLR) the distance from the lens to the film is varied in order to focus
on objects at varying distances. Over what range must a lens of 50 mm focal length vary if the camera is to
be able to focus on objects ranging in distance from infinity down to 0.80 m from the camera?
A) 12.4 mm
B) 3.33 mm
C) 2.67 mm
D) 9.67 mm
E) 5.33 mm
10) Astronomers are proud of their telescopes, and often say they can "resolve a dime at so many miles." How
many miles can you move a disk (D = 3.0 cm) from a 85-cm-diameter telescope mirror and just resolve it
using light of wavelength 536 nm? Note 1 mile =1600 meters
A) 5.9 mi
B) 24 mi
C) 120,000,000 mi
D) 120 mi
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Answer Key
Testname: QUIZ3
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
C
D
E
A
C
C
B
A
B
B
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