Physics 124B
Practice exam Ch. 22, 25,26,27
Your exam will come from the following questions

Name: __________________________ Date: _____________


1.
A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop. Which one of the following actions will not result in an induced current in the loop?
A.
Rotate the loop about an axis that is parallel to the field and passes through the center of the loop.
B.
Increase the strength of the magnetic field.
C.
Decrease the area of the loop.
D.
Decrease the strength of the magnetic field.
E.
Rotate the loop about an axis that is perpendicular to the field and passes through the center of the loop.


2.
The figure shows a uniform magnetic field that is normal to the plane of a conducting loop, which has a resistance R. Which one of the following changes will cause an induced current to flow through the resistor?
A.
decreasing the area of the loop
B.
decreasing the magnitude of the magnetic field
C.
increasing the magnitude of the magnetic field
D.
rotating the loop through 90° about an axis in the plane of the paper
E.
all of the above


3.
A conducting bar moves to the left at a constant speed v on two conducting rails joined at the left as shown. As a result of the bar moving through a constant magnetic field, a current I is induced in the indicated direction. Which one of the following directions is that of the magnetic field?
A.
toward the right
B.
toward the left
C.
parallel to the long axis of the bar
D.
into the page
E.
out of the page


4.
A 0.45-m metal rod moves 0.11 m in a direction that is perpendicular to a 0.80-T magnetic field in an elapsed time of 0.036 s. Assuming that the acceleration of the rod is zero m/s2, determine the emf that exists between the ends of the rod.
A.
1.1 V
B.
0.27 V
C.
0.076 V
D.
9.1 × 105 V
E.
This cannot be determined without knowing the orientation of the rod relative to the magnetic field.


5.
A 2.0-kg rod has a length of 1.0 m and a resistance of 4.0 ?. It slides with constant speed down a pair of frictionless vertical conducting rails that are joined at the bottom. Other than the rod, the rest of the circuit is resistanceless. A uniform magnetic field of magnitude 3.0 T is perpendicular to the plane formed by the rod and the rails as shown. Determine the speed of the rod.
A.
0.38 m/s
B.
0.90 m/s
C.
2.6 m/s
D.
5.6 m/s
E.
8.7 m/s


6.
The Earth's magnetic field passes through a square tabletop with a magnitude of
4.95 × 105 T and directed at an angle of 165° relative to the normal of the tabletop. If the tabletop has 1.50-m sides, what is the magnitude of the magnetic flux through it?
A.
1.08 × 104 Wb
B.
7.11 × 105 Wb
C.
2.88 × 105 Wb
D.
1.92 × 105 Wb
E.
3.30 × 106 Wb


7.
A circular copper loop is placed perpendicular to a uniform magnetic field of 0.50 T. Due to external forces, the area of the loop decreases at a rate of 1.26 × 103 m2/s. Determine the induced emf in the loop.
A.
3.1 × 104 V
B.
6.3 × 104 V
C.
1.2 × 103 V
D.
7.9 × 103 V
E.
3.1 V


8.
A uniform magnetic field passes through two areas, A1 and A2. The angles between the magnetic field and the normals of areas A1and A2 are 30.0° and 60.0°, respectively. If the magnetic flux through the two areas is the same, what is the ratio A1/A2?
A.
0.577
B.
0.816
C.
1.00
D.
1.23
E.
1.73


9.
A 150-turn solenoid carries a current of 12 A. The radius of the solenoid is 0.050 m; and its length is 0.18 m. Determine the magnetic flux through the circular cross-sectional area at the center of the solenoid.
A.
1.8 × 105 Wb
B.
9.9 × 105 Wb
C.
4.3 × 104 Wb
D.
7.0 × 104 Wb
E.
2.2 × 103 Wb


10.
Two conducting loops carry equal currents I in the same direction as shown in the figure. If the current in the upper loop suddenly drops to zero, what will happen to the current in the bottom loop according to Lenz's law?
A.
The current will decrease.
B.
The current will increase.
C.
The current will not change.
D.
The current will also drop to zero.
E.
The current will reverse its direction.


11.
A closed loop carries a current that increases with time. Which one of the quantities listed below relates the emf induced in the loop to the rate at which the current is increasing?
A.
resistance of the loop
B.
capacitance of the loop
C.
self-inductance of the loop
D.
power dissipated by the loop
E.
mutual inductance of the loop


12.
The figure shows a circular, conducting loop that is connected to a 5.0-V battery and a switch S. Immediately after the switch S is closed, the current through the loop changes at a rate of 15 A/s and the emf induced in the loop has a magnitude of 5.0 V. Determine the self-inductance of the coil.
A.
0.33 H
B.
0.60 H
C.
1.5 H
D.
3.0 H
E.
5.0 H


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

13.
Immediately after the switch S is closed, which one of the following statements is true?
A.
An induced current will flow from right to left in R.
B.
An induced current will flow from left to right in r.
C.
A magnetic field that points toward B appears inside coil 1.
D.
An induced magnetic field that points toward B appears inside coil 2.
E.
A current will pass through r, but there will be no current through R.


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

14.
Assume the switch S has been closed for a long time. Which one of the following statements is true?
A.
An induced current will flow from right to left in R.
B.
An induced current will flow from left to right in r.
C.
A magnetic field that points toward B appears inside coil 1.
D.
An induced magnetic field that points toward B appears inside coil 2.
E.
A current will pass through r, but there will be no current through R.


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

15.
Assume S has been closed for a long time. Which one of the following statements is true when coil 1 and its core are moved toward point B?
A.
There is no induced current in r.
B.
There is a magnetic field in coil 1 that points toward B.
C.
There is an induced current in R that flows from left to right.
D.
There is an induced current in R that flows from right to left.
E.
There is an induced magnetic field in coil 2 that points toward B.


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

16.
Assume that S has been closed for a long time. Which one of the following changes will not result in an induced current in coil 2 that flows from left to right through R.
A.
Coil 1 and its core are moved toward A.
B.
Coil 2 and its core are moved toward B
C.
Coil 2 and its core are moved toward C.
D.
The switch S is opened
E.
The iron core is removed from coil 1.


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

17.
Assume that S has been closed for a long time. Which one of the following changes will result in an induced magnetic field in coil 2 that points toward C?
A.
The switch S is opened.
B.
The iron core is removed from coil 1.
C.
Coil 1 and its core are moved toward A.
D.
Coil 1 and its core are moved toward B.
E.
Coil 2 and its core are moved toward C.


Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch.
Reference: Ref 22-5

18.
Assume that S has been closed for a long time. Which one of the following statements is true if S is suddenly opened?
A.
There is no induced current through R.
B.
There is no induced magnetic field in coil 2.
C.
There is an induced current in R that flows from right to left.
D.
There is an induced magnetic field in coil 2 that points toward C.
E.
There is an induced magnetic field in coil 2 that points toward B.


19.
The current in the secondary coil of a step-up transformer is 0.86 A when the current in the primary coil is 4.8 A. Determine the turns ratio, Ns/Np, of the transformer.
A.
5.6
B.
4.1
C.
0.24
D.
0.18
E.
0.12


20.
A transformer changes 120 V across the primary to 1200 V across the secondary. If the secondary coil has 800 turns, how many turns does the primary coil have?
A.
40
B.
80
C.
100
D.
400
E.
4000


21.
Which one of the following statements concerning rays is false?
A.
Rays point in the direction of the wave velocity.
B.
Rays point outward from the wave source.
C.
Rays are parallel to the wave front.
D.
Rays are radial lines that originate from a point source of waves.
E.
Rays for a plane wave are parallel to each other.


22.
Which one of the following statements is not a characteristic of a plane mirror?
A.
The image is real.
B.
The magnification is +1.
C.
The image is always upright.
D.
The image is reversed right to left.
E.
The image and object distances are equal in magnitude.


23.
An object is placed near two perpendicular plane mirrors as shown in the figure. How many images will be formed?
A.
1
B.
2
C.
3
D.
4
E.
5


24.
A ray of light is reflected from two plane mirror surfaces as shown in the figure. What are the correct values of α and ??
 
Value of α
Value of ?
 
A.
 
26°
26°
 
B.
 
26°
64°
 
C.
 
38°
52°
 
D.
 
52°
26°
 
E.
 
64°
26°
 


25.
An object is placed 1 m in front of a plane mirror. An observer stands 3 m behind the object. For what distance must the observer focus his eyes in order to see the image of the object?
A.
1 m
B.
2 m
C.
3 m
D.
4 m
E.
5 m


26.
The focal length of a spherical concave mirror is 20 cm. What is its radius of curvature?
A.
5 cm
B.
10 cm
C.
20 cm
D.
40 cm
E.
50 cm


27.
Which one of the following statements concerning a convex mirror is true?
A.
It can form a real image.
B.
It must be spherical in shape.
C.
The image will always be inverted relative to the object.
D.
It produces a larger image than a plane mirror does for the same object distance.
E.
The image it produces is closer to the mirror than it would be in a plane mirror for the same object distance.


28.
A concave mirror has a radius of curvature of 30.0 cm. How close to the mirror should an object be placed so that the rays travel parallel to each other after reflection?
A.
10.0 cm
B.
15.0 cm
C.
30.0 cm
D.
45.0 cm
E.
60.0 cm


29.
Which one of the following statements concerning the image formed by a concave spherical mirror is true?
A.
When the object distance is less than the focal length, the image is virtual.
B.
When the object distance is larger than the focal length, the image is virtual.
C.
When the object is at the center of curvature, the image is formed at infinity.
D.
When the object distance is less than the focal length, the image is inverted relative to the object.
E.
When the object distance is larger than the focal length, the image is upright relative to the object.


An object is placed in front of a concave spherical mirror as shown below. The three rays 1, 2, and 3, leave the top of the object and, after reflection, converge at a point on the top of the image. Ray 1 is parallel to the principal axis, ray 2 passes through F, and ray 3 passes through C.
Reference: Ref 25-1

30.
Which ray(s) will pass through F after reflection?
A.
1 only
B.
2 only
C.
3 only
D.
both 1 and 2
E.
1, 2, and 3


An object is placed in front of a concave spherical mirror as shown below. The three rays 1, 2, and 3, leave the top of the object and, after reflection, converge at a point on the top of the image. Ray 1 is parallel to the principal axis, ray 2 passes through F, and ray 3 passes through C.
Reference: Ref 25-1

31.
Which ray(s) will reflect back on itself (themselves)?
A.
1 only
B.
2 only
C.
3 only
D.
both 1 and 2
E.
1, 2, and 3


An object is placed in front of a concave spherical mirror as shown below. The three rays 1, 2, and 3, leave the top of the object and, after reflection, converge at a point on the top of the image. Ray 1 is parallel to the principal axis, ray 2 passes through F, and ray 3 passes through C.
Reference: Ref 25-1

32.
Which one of the following groups of terms best describes the image?
A.
real, upright, enlarged
B.
real, inverted, reduced
C.
virtual, upright, enlarged
D.
real, inverted, enlarged
E.
virtual, inverted, reduced


33.
A concave mirror in an amusement park has a radius of curvature of 4.0 m. A child stands in front of the mirror so that she appears 2.5 times taller than her actual height. If the image is upright, how far is she standing from the mirror?
A.
1.2 m
B.
3.5 m
C.
2.8 m
D.
4.0 m
E.
7.0 m


34.
A convex mirror in an amusement park has a radius of curvature of 3.00 m. A man stands in front of the mirror so that his image is half as tall as his actual height. At what distance must the man focus his eyes in order to see his image?
A.
2.25 m
B.
3.00 m
C.
4.50 m
D.
5.00 m
E.
6.75 m


35.
A concave mirror has a radius of curvature of 20 cm. For which one of the following object distances will the image be real, inverted and smaller than the object?
A.
5 cm
B.
10 cm
C.
15 cm
D.
18 cm
E.
25cm


36.
The table lists the index of refraction for various substances at 20 °C for light with a wavelength of 589 nm in a vacuum. Through which substance will light with a vacuum wavelength of 589 nm travel with the greatest speed?
A.
fused quartz
B.
crown glass
C.
ethyl alcohol
D.
carbon tetrachloride
E.
crystalline quartz


37.
The bending of light as it moves from one medium to another with differing indices of refraction is due to a change in what property of the light?
A.
amplitude
B.
period
C.
frequency
D.
speed
E.
color


38.
When certain light rays pass from a vacuum into a block of an unknown material, the measured index of refraction of the material is 3.50. What is the speed of light inside the block?
A.
1.0 × 107 m/s
B.
4.8 × 107 m/s
C.
8.6 × 107 m/s
D.
1.9 × 108 m/s
E.
2.9 × 108 m/s


39.
Blue light with a wavelength of 425 nm passes from a vacuum into a glass lens; and the index of refraction is found to be 1.65. The glass lens is replaced with a plastic lens. The index of refraction for the plastic lens is 1.54. In which one of the two lenses does the light have the greatest speed and what is that speed?
A.
glass, 2.28 × 108 m/s
B.
plastic, 2.13 × 108 m/s
C.
glass, 1.82 × 108 m/s
D.
plastic, 1.95 × 108 m/s
E.
The speed of the blue light is the same in the vacuum and both lenses; and it is 3.00 × 108 m/s.


40.
A ray of light passes from air into a block of glass with a refractive index of 1.50 as shown in the figure.

Note: The drawing is not to scale.
What is the value of the distance D?
A.
1.42 cm
B.
1.66 cm
C.
1.90 cm
D.
2.14 cm
E.
2.38 cm


41.
A fish swims 2.00 m below the surface of a pond. At what apparent depth does the fish appear to swim if viewed from directly above? The index of refraction of water is 1.33.
A.
1.33 m
B.
1.50 m
C.
2.00 m
D.
2.66 m
E.
3.00 m


42.
A scuba diver shines a flashlight from beneath the surface of water (n = 1.33) such that the light strikes the water-air boundary with an angle of incidence of 43°. At what angle is the beam refracted?
A.
31°
B.
43°
C.
48°
D.
65°
E.
90°


43.
The figure shows the path of a portion of a ray of light as it passes through three different materials. Note: The figure is drawn to scale.

What can be concluded concerning the refractive indices of these three materials?
A.
n1 < n2 < n3
B.
n1 > n2 > n3
C.
n3 < n1 < n2
D.
n2 < n1 < n3
E.
n1 < n3 < n2


The figure shows the path of a ray of light as it travels through air and crosses a boundary into water.

The index of refraction of water for this light is 1.33.
Reference: Ref 26-1

44.
What is the speed of this ray of light as it travels through the water?
A.
1.54 × 108 m/s
B.
2.26 × 108 m/s
C.
2.86 × 108 m/s
D.
3.99 × 108 m/s
E.
4.43 × 109 m/s


The figure shows the path of a ray of light as it travels through air and crosses a boundary into water.

The index of refraction of water for this light is 1.33.
Reference: Ref 26-1

45.
What is the angle of refraction for this situation?
A.
0.37°
B.
0.65°
C.
22°
D.
41°
E.
60°


46.
Complete the following statement: Fiber optics make use of
A.
total internal reflection.
B.
polarization.
C.
chromatic aberration.
D.
Brewster's angle.
E.
dispersion.


47.
Which one of the following expressions determines the critical angle for quartz (n = 1.5) immersed in oil (n = 1.1)?
A.
?c = 1.5/1.1
B.
?c = 1.5/1.1
C.
?c = sin1(1.1/1.5)
D.
?c = sin(1.1/1.5)
E.
?c = tan1(1.1/1.5)


48.
A fiber optic line is composed of a core with an index of refraction of 1.47 and cladding with an index of 1.31. Which one of the following relations best describes angles of incidence ? that will result in total internal reflection within the fiber optic line?
A.
? < 63°
B.
? > 63°
C.
? < 27°
D.
? > 27°
E.
0 ≤ ? 90°


49.
A ray of light originating in oil (n = 1.21) is incident at the Brewster angle upon a flat surface of a quartz crystal (n = 1.458). Determine the angle of incidence for this ray.
A.
0.82°
B.
1.2°
C.
40°
D.
50°
E.
56°


Light in air is incident on a plastic plate at the Brewster angle. The angle of refraction is 35.0°.
Reference: Ref 26-2

50.
Determine the Brewster angle.
A.
35.0°
B.
55.0°
C.
46.5°
D.
43.5°
E.
82.3°


Light in air is incident on a plastic plate at the Brewster angle. The angle of refraction is 35.0°.
Reference: Ref 26-2

51.
What is the index of refraction of the plastic plate?
A.
1.58
B.
1.36
C.
1.43
D.
1.61
E.
1.74


52.
A ray of green light travels through air and is refracted as it enters a glass prism shown in the figure. An unknown liquid is in contact with the right side of the prism. The light then follows the path shown. Which one of the following statements concerning this situation is true?
A.
The frequency of the light changes inside the prism.
B.
The index of refraction of the glass is smaller than that of air.
C.
The index of refraction of the unknown liquid is the same as that of the glass.
D.
The speed of light is larger in the liquid than in the glass.
E.
The refractive index of the liquid is the same as that of air.


53.
An object is placed 4.0 cm from a thin converging lens with a focal length of 12 cm. Which one of the following statements is true concerning the image?
A.
The image is virtual and 6.0 cm from the lens.
B.
The image is virtual and 12 cm from the lens.
C.
The image is real and 3.0 cm from the lens.
D.
The image is real and 6.0 cm from the lens.
E.
The image is real and 12 cm from the lens.


54.
A converging lens is used to focus light from a small bulb onto a book. The lens has a focal length of 10.0 cm and is located 40.0 cm from the book. Determine the distance from the lens to the light bulb.
A.
8.6 cm
B.
13 cm
C.
20 cm
D.
30 cm
E.
50 cm


55.
When an object is placed 20 cm from a diverging lens, a reduced image is formed. Which one of the following statements is necessarily true?
A.
The image is inverted.
B.
The image could be real.
C.
The image distance must be greater than 20 cm.
D.
The focal length of the lens may be less than 20 cm.
E.
The refractive power of the lens must be greater than 0.05 diopters.


56.
A 6.0-cm object is placed 30.0 cm from a lens. The resulting image height has a magnitude of 2.0 cm; and the image is inverted. What is the focal length of the lens?
A.
7.5 cm
B.
15.0 cm
C.
22.5 cm
D.
30.0 cm
E.
45.0 cm


57.
A converging lens with a focal length of 12 cm produces a 3-cm high virtual image of a 1-cm high object. Which entry in the table below is correct?
 
image distance
location of image
 
A.
 
8 cm
 
same side of lens as object
 
B.
 
8 cm
 
opposite side of lens from object
 
C.
 
12 cm
 
opposite side of lens from object
 
D.
 
24 cm
 
opposite side of lens from object
 
E.
 
24 cm
 
same side of lens as object
 


A diverging lens has a focal length of –10 cm. A 3-cm object is placed 25 cm from the lens.
Reference: Ref 26-6

58.
What is the magnification of the image?
A.
+0.3
B.
0.3
C.
+0.7
D.
0.7
E.
+0.8


A diverging lens has a focal length of –10 cm. A 3-cm object is placed 25 cm from the lens.
Reference: Ref 26-6

59.
Determine the approximate distance between the object and the image.
A.
7 cm
B.
10 cm
C.
18 cm
D.
32 cm
E.
35 cm


A 4.0-cm object is placed 30.0 cm from a converging lens that has a focal length of 10.0 cm as shown in the diagram.

Note: The diagram is not drawn to scale.
Reference: Ref 26-7

60.
Where is the image located?
A.
15 cm to the left of the lens
B.
7.5 cm to the left of the lens
C.
7.5 cm to the right of the lens
D.
15 cm to the right of the lens
E.
30 cm to the right of the lens


A 4.0-cm object is placed 30.0 cm from a converging lens that has a focal length of 10.0 cm as shown in the diagram.

Note: The diagram is not drawn to scale.
Reference: Ref 26-7

61.
Determine the height and orientation of the image.
A.
2 cm and upright
B.
1 cm and inverted
C.
2 cm and inverted
D.
8 cm and upright
E.
8 cm and inverted


A 4.0-cm object is placed 30.0 cm from a converging lens that has a focal length of 10.0 cm as shown in the diagram.

Note: The diagram is not drawn to scale.
Reference: Ref 26-7

62.
A second converging lens is placed 20.0 cm to the right of the lens shown in the figure. Determine the focal length of the second lens if an inverted image (relative to the object in the diagram) is formed 13.3 cm to the right of the first lens.
A.
1.33 cm
B.
6.67 cm
C.
13.3 cm
D.
15.4 cm
E.
19.7 cm


63.
Complete the following sentence: The term coherence relates to
A.
the phase relationship between two waves.
B.
the polarization state of two waves.
C.
the diffraction of two waves.
D.
the amplitude of two waves.
E.
the frequency of two waves.


64.
Two identical light waves, A and B, are emitted from different sources and meet at a point P. The distance from the source of A to the point P is A; and the source of B is a distance B from P. Which of the following statements is necessarily true concerning the interference of the two waves?
A.
A and B will interfere constructively because their amplitudes are the same.
B.
A and B will interfere constructively if A = B.
C.
A and B will interfere destructively if A – B = mλ where m = 0, 1, 2, 3, ...
D.
A and B will interfere destructively if A is not equal to B.
E.
A and B will interfere constructively because their wavelengths are the same.


65.
Two slits separated by 2.00 × 105 m are illuminated by light of wavelength 500 nm. If the screen is 8.00 m from the slits, what is the distance between the m = 0 and m = 1 bright fringes?
A.
1.25 cm
B.
2.50 cm
C.
5.00 cm
D.
10.0 cm
E.
20.0 cm


66.
The figure shows the interference pattern produced when light of wavelength 500 nm is incident on two slits. Fringe A is equally distant from each slit. By what distance is fringe B closer to one slit than the other?
A.
250 nm
B.
500 nm
C.
750 nm
D.
1000 nm
E.
1500 nm


The figure shows the interference pattern obtained in a double-slit experiment using light of wavelength 600 nm.
Reference: Ref 27-1

67.
Which fringe is the same distance from both slits?
A.
A
B.
B
C.
C
D.
D
E.
E


The figure shows the interference pattern obtained in a double-slit experiment using light of wavelength 600 nm.
Reference: Ref 27-1

68.
Which fringe is the third order maximum?
A.
A
B.
B
C.
C
D.
D
E.
E


The figure shows the interference pattern obtained in a double-slit experiment using light of wavelength 600 nm.
Reference: Ref 27-1

69.
Which one of the following phenomena would be observed if the wavelength of light were increased?
A.
The fringes would be brighter.
B.
More bright fringes would appear on the screen.
C.
The distance between dark fringes would decrease.
D.
Single-slit diffraction effects would become non-negligible.
E.
The angular separation between bright fringes would increase.


The figure shows the interference pattern obtained in a double-slit experiment using light of wavelength 600 nm.
Reference: Ref 27-1

70.
Which one of the following phenomena would be observed if the distance between the slits were increased?
A.
The fringes would become brighter.
B.
The central bright fringe would change position.
C.
The distance between dark fringes would increase.
D.
The distance between bright fringes would increase.
E.
The angular separation between the dark fringes would decrease.


71.
A 4.0 × 102-nm thick film of kerosene (n = 1.2) is floating on water. White light is normally incident on the film. What is the visible wavelength in air that has a maximum intensity after the light is reflected? Note: the visible wavelength range is 380 nm to 750 nm.
A.
380 nm
B.
430 nm
C.
480 nm
D.
530 nm
E.
580 nm


72.
Light of wavelength λ in vacuum strikes a lens that is made of glass with index of refraction 1.6. The lens has been coated with a film of thickness t and index of refraction 1.3. For which one of the following conditions will there be no reflection?
A.
B.
C.
D.
E.


73.
Which one of the following statements best explains why the diffraction of sound is more apparent than the diffraction of light under most circumstances?
A.
Sound requires a physical medium for propagation.
B.
Sound waves are longitudinal, and light waves are transverse.
C.
Light waves can be represented by rays while sound waves cannot.
D.
The speed of sound in air is six orders of magnitude smaller than that of light.
E.
The wavelength of light is considerably smaller than the wavelength of sound.


74.
Light of wavelength 700.0 nm passes through a diffraction grating. The m = 0 and m = 1 bright spots are 6.0 cm apart on a screen positioned 2.0 cm from the grating. What is the spacing between the slits in the grating?
A.
233 nm
B.
420 nm
C.
467 nm
D.
738 nm
E.
1240 nm


75.
Light of wavelength 625 nm shines through a single slit of width 0.32 mm and forms a diffraction pattern on a flat screen located 8.0 m away. Determine the distance between the middle of the central bright fringe and the first dark fringe.
A.
0.156 cm
B.
0.516 cm
C.
1.56 cm
D.
5.16 cm
E.
6.51 cm


76.
Light of 600.0 nm is incident on a single slit of width 6.5 ?m. The resulting diffraction pattern is observed on a nearby screen and has a central maximum of width 3.5 m. What is the distance between the screen and the slit?
A.
9.5 m
B.
19 m
C.
38 m
D.
57 m
E.
76 m


77.
A monochromatic beam of microwaves with a wavelength of 0.052 m is directed at a rectangular opening of width 0.35 m. The resulting diffraction pattern is measured along a wall 8.0 m from the opening. What is the distance between the first- and second-order dark fringes?
A.
1.3 m
B.
1.8 m
C.
2.1 m
D.
2.5 m
E.
3.7 m


78.
Light with a wavelength of 644 nm uniformly illuminates a single slit. What is the width of the slit if the first-order dark fringe is located at ? = 0.125°?
A.
9.42 × 104 m
B.
7.60 × 104 m
C.
4.71 × 104 m
D.
3.80 × 104 m
E.
2.95 × 104 m


79.
The Hubble Space Telescope in orbit above the Earth has a 2.4 m circular aperture. The telescope has equipment for detecting ultraviolet light. What is the minimum angular separation between two objects that the Hubble Space Telescope can resolve in ultraviolet light of wavelength 95 nm?
A.
4.8 × 108 rad
B.
7.0 × 108 rad
C.
1.9 × 107 rad
D.
1.5 × 107 rad
E.
3.3 × 109 rad


80.
Which one of the following statements provides the most convincing evidence that electromagnetic waves have a transverse character?
A.
Electromagnetic waves can be refracted.
B.
Electromagnetic waves can be reflected.
C.
Electromagnetic waves can be polarized.
D.
Electromagnetic waves can be diffracted.
E.
Electromagnetic waves exhibit interference.


81.
Solved problem. You must show all work clearly and completely for full cedit.

Two glass plates are separated by a human hair at one end. When the plates are illuminated with green light of 550nm, 12 dark fringes per cm appear on the top plate. If the plates are 20 cm long, how thick is the hair?
Show how the equations are derived, including phase shift diagrams.


Answer Key

1. A
2. E
3. E
4. E
5. E
6. A
7. B
8. A
9. B
10. B
11. C
12. A
13. A
14. E
15. D
16. B
17. D
18. E
19. A
20. B
21. C
22. A
23. C
24. B
25. E
26. D
27. E
28. B
29. A
30. A
31. C
32. B
33. A
34. A
35. E
36. C
37. D
38. C
39. D
40. E
41. B
42. D
43. C
44. B
45. D
46. A
47. C
48. B
49. D
50. B
51. C
52. C
53. A
54. B
55. D
56. A
57. E
58. A
59. C
60. D
61. C
62. E
63. A
64. B
65. E
66. D
67. B
68. E
69. E
70. E
71. C
72. E
73. E
74. D
75. C
76. B
77. A
78. E
79. A
80. C
81.
65.7 micrometers