MC PHY 245 E2
85) A thin lens projects an image of a man as shown in the figure. Rays marked A, B, and C travel to the lens from the man's ear. Draw the paths of these three rays after they have passed through the lens. Note that A is parallel to the principal axis, B goes through the center of the lens, C goes through the focal point on the left, and the point marked f is the focal point on the right of the lens.
N/A
100) Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum constructive interference is to occur at point P, the two beams must travel paths that differ by A) a whole number of wavelengths. B) an odd number of half-wavelengths. C) a whole number of half-wavelengths.
a
101) If a sheet containing two very thin slits is heated (without damaging it), what happens to the angular location of the first-order interference minimum? A) It moves toward the centerline. B) It moves away from the centerline. C) It doesn't change.
a
106) Which of the following changes would increase the separation between the bright fringes in the diffraction pattern formed by a diffraction grating? A) Increase the wavelength of the light used. B) Increase the separation between the slits. C) Immerse the apparatus in water. D) All of these. E) None of these.
a
107) Light in a frozen block of ice reflects off the ice-air interface at the surface of the block. What phase shift does it undergo? A) 0° B) 90° C) 180° D) 270° E) It does not undergo any phase shift.
a
11) A proton, moving east, enters a magnetic field. Because of this magnetic field the proton curves downward. We may conclude that the magnetic field must have a component A) towards the south. B) towards the north. C) towards the west. D) upward. E) downward.
a
12) An electron is moving to the right, as shown in the figure. Suddenly it encounters uniform magnetic field pointing out of the page. Which one of the three paths shown will it follow in the field? A) path a B) path b C) path c
a
24) An electron has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component A) to the west. B) to the east. C) upward. D) downward. E) to the north.
a
25) A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the poles of a magnet, as shown in the figure If there is a current I flowing through this coil in the direction shown, what is the direction of the force acting on section AB of this coil? A) perpendicular to and into the page B) perpendicular to and out of the page C) in the direction of the magnetic field D) in the opposite direction of the magnetic field E) The force is zero.
a
31) A ring with a clockwise current (as viewed from above the ring) is situated with its center directly above another ring, which has a counter-clockwise current, as shown in the figure. In what direction is the net magnetic force exerted on the top ring due to the bottom ring? A) upward B) downward C) to the left D) to the right E) The net force is zero
a
32) A long, straight, horizontal wire carries current toward the east. A proton moves toward the east alongside and just south of the wire. What is the direction of the magnetic force on the proton? A) toward the north B) toward the south C) upward D) downward E) toward the east.
a
37) Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the radius of the solenoid is doubled to 2b, but all the other quantities remain the same, the magnetic field inside the solenoid will A) remain the same. B) become twice as strong as initially. C) become one-half as strong as initially. D) become four times as strong as initially. E) become one-fourth as strong as initially
a
40) A coil lies flat on a tabletop in a region where the magnetic field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the sense of the induced current in this coil as the field fades? A) The induced current flows counterclockwise. B) The induced current flows clockwise. C) There is no induced current in this coil. D) The current flows clockwise initially, and then it flows counterclockwise before stopping.
a
51) A circular wire ring is situated above a long straight wire, as shown in the figure. The straight wire has a current I flowing to the right, and this current is increasing at a constant rate. Which of the following statements is true? A) There is an induced current in the wire ring, directed in clockwise orientation. B) There is an induced current in the wire ring, directed in a counterclockwise orientation. C) There is no induced current in the wire ring.
a
65) Light enters air from water. The angle of refraction will be A) greater than the angle of incidence. B) equal to the angle of incidence. C) less than the angle of incidence.
a
76) Which statements about images are correct? (There could be more than one correct choice.) A) A virtual image cannot be formed on a screen. B) A virtual image cannot be viewed by the unaided eye. C) A virtual image cannot be photographed. D) A real image must be erect. E) Mirrors always produce real images because they reflect light.
a
81) Single convex spherical mirrors produce images that A) are always smaller than the actual object. B) are always larger than the actual object. C) are always the same size as the actual object. D) could be larger than, smaller than, or the same size as the actual object, depending on the placement of the object. E) are sometimes real.
a
9) An electron, moving west, enters a magnetic field. Because of this field the electron curves upward. We may conclude that the magnetic field must have a component A) towards the north. B) towards the south. C) upward. D) downward. E) towards the west
a
90) If a object is placed between a convex lens and its focal point, the image formed is A) virtual and upright. B) virtual and inverted. C) real and upright. D) real and inverted.
a
97) A double-slit interference experiment is performed in the air. Later, the same apparatus is immersed in benzene (which has an index of refraction of 1.50), and the experiment is repeated. When the apparatus is in benzene, you observe that the interference fringes are A) more closely spaced than when the apparatus is in air. B) equally spaced as when the apparatus is in air. C) more widely spaced than when the apparatus is in air.
a
87) Which of the following terms describe lenses that are thicker at the center than at the edges? (There could be more than one correct choice.) A) converging lenses B) diverging lenses C) concave lenses D) convex lenses
ad
103) If a sheet containing a single thin slit is heated (without damaging it) and therefore expands, what happens to the width of the central bright diffraction region on a distant screen? A) It gets narrower. B) It gets wider. C) It doesn't change.
b
105) Radio waves are diffracted by large objects such as buildings, whereas light is not noticeably diffracted. Why is this? A) Radio waves are unpolarized, whereas light is normally polarized. B) The wavelength of light is much smaller than the wavelength of radio waves. C) The wavelength of light is much greater than the wavelength of radio waves. D) Radio waves are coherent and light is usually not coherent. E) Radio waves are polarized, whereas light is usually unpolarized.
b
109) When a beam of light that is traveling in glass strikes an air boundary at the surface of the glass, there is A) a 90° phase change in the reflected beam. B) no phase change in the reflected beam. C) a 180° phase change in the reflected beam. D) a 60° phase change in the reflected beam. E) a 45° phase change in the reflected beam.
b
16) A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. A uniform electric field is also present. Due to the combined effect of both fields, the particle does not change its velocity. What is the direction of the electric field? A) along the -y-axis B) along the +y-axis C) along the -x-axis D) along the +x-axis E) along the -z-axis
b
2) A straight bar magnet is initially 4 cm long, with the north pole on the right and the south pole on the left. If you cut the magnet in half, the right half will A) contain only a north pole. B) contain a north pole on the right and a south pole on the left. C) contain only a south pole. D) no longer contain any poles.
b
27) When the switch is closed in the circuit shown in the figure, the wire between the poles of the horseshoe magnet deflects upward. From this you can conclude that the left end of the magnet is A) a north magnetic pole. B) a south magnetic pole. C) There is not enough information given to answer the question.
b
33) A long, straight, horizontal wire carries current toward the east. An electron moves toward the east alongside and just south of the wire. What is the direction of the magnetic force on the electron? A) toward the north B) toward the south C) upward D) downward E) toward the west.
b
41) A coil lies flat on a level tabletop in a region where the magnetic field vector points straight up. The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the induced current in this coil as the field increases? A) counterclockwise B) clockwise C) clockwise initially, then counterclockwise before stopping D) There is no induced current in this coil.
b
42) A coil lies flat on a horizontal tabletop in a region where the magnetic field points straight down. The magnetic field disappears suddenly. When viewed from above, what is the direction of the induced current in this coil as the field disappears? A) counterclockwise B) clockwise C) clockwise initially, then counterclockwise before stopping D) There is no induced current in this coil.
b
43) Two solenoids are close to each other, as shown in the figure, with the switch S open. When the switch is suddenly closed, which way will the induced current flow through the galvanometer in the left-hand solenoid? A) from left to right B) from right to left C) There will be no induced current through the galvanometer
b
44) An outer metal ring surrounds an inner metal ring, as shown in the figure. The current in the outer ring is counterclockwise and decreasing. What is the direction of the induced current in the inner ring? A) clockwise B) counterclockwise C) There is no induced current in the inner ring.
b
47) A circular coil of copper wire is lying flat on a horizontal table. A bar magnet is held above the center of the coil with its south pole downward. The magnet is released from rest and falls toward the coil. As viewed from above, what is the direction of the current induced in the coil as the magnet approaches the coil? A) counterclockwise B) clockwise C) No current is induced in the coil. D) An emf but no current is induced in the coil.
b
49) A bar magnet is oriented above a copper ring, as shown in the figure. If the magnet is pulled upward, what is the direction of the current induced in the ring, as viewed from above? A) There is no current in the ring. B) counterclockwise C) clockwise
b
53) A transformer is a device that normally A) operates on either dc or ac. B) operates only on ac. C) operates only on dc.
b
6) An electron moving along the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, then the magnetic field must have a component A) along the +z-axis B) along the -z-axis C) along the -x-axis D) along the +y-axis E) along the -y-axis
b
63) Two light beams of different frequency but the same intensity fall on a black (totally absorbing) surface, striking perpendicular to the surface. Which of the following statements are true? (There could be more than one correct choice.) A) The high-frequency beam exerts more pressure on the surface. B) Both beams exert the same pressure on the surface. C) If the surface were painted white (totally reflecting), the pressure on it would be less than when it was black. D) Painting the surface white would not affect the pressure on it due to these beams. E) The light beams exert no pressure on the surface because light is just energy.
b
68) The critical angle for a beam of light passing from water into air is 48.8°. This means that all light rays with an angle of incidence in the water that is greater than 48.8° will be A) totally absorbed by the water. B) totally reflected. C) partially reflected and partially transmitted. D) totally transmitted.
b
83) An upright object is 50 cm from a concave mirror of radius 60 cm. The character of the image is A) real and upright B) real and inverted C) virtual and upright D) virtual and inverted
b
89) A convex lens has focal length f. If an object is placed at a distance beyond 2f from the lens on the principal axis, the image is located at a distance from the lens A) of 2f. B) between f and 2f. C) of f. D) between the lens and f. E) of infinity.
b
99) Two light sources are said to be coherent if they are A) of the same frequency. B) of the same frequency, and maintain a constant phase difference. C) of the same amplitude, and maintain a constant phase difference. D) of the same frequency and amplitude.
b
86) Which of the following terms describe lenses that are thinner at the center than at the edges? (There could be more than one correct choice.) A) converging lenses B) diverging lenses C) concave lenses D) convex lenses
bc
58) Which of the following statements about electromagnetic waves in free space are true? (There could be more than one correct choice.) A) The higher-frequency travel faster than the lower-frequency waves. B) The higher-frequency waves have shorter wavelengths than the lower-frequency waves. C) The wavelengths of the visible waves are some of the longest electromagnetic waves. D) The wavelengths of the visible waves are some of the shortest electromagnetic waves. E) The electric field vector is always at right angles to the magnetic field vector.
be
96) Monochromatic coherent light shines through a pair of slits. If the wavelength of the light is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.) A) The distance between the maxima stays the same. B) The distance between the maxima decreases. C) The distance between the minima stays the same. D) The distance between the minima increases. E) The distance between the minima decreases.
be
1) If you were to cut a small permanent bar magnet in half, A) one piece would be a magnetic north pole and the other piece would be a south pole. B) neither piece would be magnetic. C) each piece would in itself be a smaller bar magnet with both north and south poles. D) None of these statements is true.
c
10) A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component A) towards the west. B) towards the east. C) towards the south. D) towards the north. E) downward
c
102) In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe in the resulting diffraction pattern? A) It stays the same. B) It becomes narrower. C) It becomes wider.
c
104) What principle is responsible for light spreading as it passes through a narrow slit? A) refraction B) polarization C) diffraction D) dispersion
c
108) Light reflects off the surface of Lake Superior. What phase shift does it undergo? A) 0° B) 90° C) 180° D) 270° E) It does not undergo any phase shift
c
110) When a beam of light that is traveling in air is reflected by a glass surface, there is A) a 90° phase change in the reflected beam. B) no phase change in the reflected beam. C) a 180° phase change in the reflected beam. D) a 60° phase change in the reflected beam. E) a 45° phase change in the reflected beam.
c
15) A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. Because of an electric field along the +y-axis, the charge particle does not change velocity. What is the sign of this particle? A) positive B) negative C) The particle could be either positive or negative. D) None of the above choices is correct.
c
19) If a calculated quantity has units of T ∙ m/A, that quantity could be A) an electric field. B) an electric potential. C) μ0. D) a magnetic field. E) a magnetic torque.
c
21) A charged particle moves with a constant speed through a region where a uniform magnetic field is present. If the magnetic field points straight upward, the magnetic force acting on this particle will be strongest when the particle moves A) straight upward. B) straight downward. C) in a plane parallel to Earth's surface. D) upward at an angle of 45° above the horizontal.
c
22) A negatively-charged particle moves across a constant uniform magnetic field that is perpendicular to the velocity of the particle. The magnetic force on this particle A) causes the particle to speed up. B) causes the particle to slow down. C) causes the particle to accelerate. D) is in the same direction as the particle's velocity. E) is opposite the direction of the particle's velocity.
c
23) At a particular instant, a proton moves toward the east in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is A) zero. B) upward. C) toward the north. D) toward the south. E) downward.
c
26) A wire is carrying current vertically downward. What is the direction of the force on this wire due to Earth's magnetic field? A) horizontally towards the north B) horizontally towards the south C) horizontally towards the east D) horizontally towards the west E) vertically upward
c
29) Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in the same direction, A) one wire is lifted slightly while the other wire is forced downward against the table's surface. B) both wires are lifted slightly. C) the wires pull toward each other. D) the wires push away from each other.
c
3) Which one of the following statements is correct? A) Earth's geographic north pole is the north pole of Earth's magnetic field. B) Earth's geographic south pole is the south pole of Earth's magnetic field. C) The north pole of a magnet points towards Earth's geographic north pole. D) The north pole of a magnet points towards Earth's geographic south pole. E) None of the above statements is correct.
c
38) Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the length of the solenoid becomes twice as long (to 2L), but all other quantities remained the same, the magnetic field inside the solenoid will A) remain the same. B) become twice as strong as initially. C) become one-half as strong as initially. D) become four times as strong as initially. E) become one-fourth as strong as initially.
c
39) A flat coil is in a uniform magnetic field. The magnetic flux through the coil is greatest when the plane of its area is A) parallel to the magnetic field. B) at 45° with the magnetic field. C) perpendicular to the magnetic field.
c
46) A circular coil lies flat on a horizontal surface. A bar magnet is held fixed above the center of the coil with its north pole pointing downward. What is the direction of the induced current in the coil, as viewed from above? A) clockwise B) counterclockwise C) There is no current in the coil.
c
48) A circular coil of copper wire is lying flat on a horizontal table. A bar magnet is held above the center of the coil with its south pole downward. The magnet and the coil are now both raised upward with the same velocities. As viewed from above, what is the direction of the current induced in the coil as the magnet approaches the coil? A) counterclockwise B) clockwise C) No current is induced in the coil. D) An emf but no current is induced in the coil.
c
5) A charged particle that is moving in a static uniform magnetic field A) will always experience a magnetic force, regardless of its direction of motion. B) may experience a magnetic force which will cause its speed to change. C) may experience a magnetic force, but its speed will not change. D) may experience a magnetic force, but its direction of motion will not change. E) None of the above statements are true.
c
50) A bar magnet is oriented above a copper ring, as shown in the figure. If the magnet is kept fixed while the ring is dropped, what is the direction of the current induced in the ring, as viewed from below the ring? A) There is no current in the ring. B) counterclockwise C) clockwise
c
52) A transformer is a device used to A) transform an alternating current into a direct current. B) transform a direct current into an alternating current. C) increase or decrease an ac voltage. D) increase or decrease a dc voltage.
c
55) Which one of the following lists gives the correct order of the electromagnetic spectrum from low to high frequencies? A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays B) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays C) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays D) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
c
57) In an electromagnetic wave in free space, the electric and magnetic fields are A) parallel to one another and perpendicular to the direction of wave propagation. B) parallel to one another and parallel to the direction of wave propagation. C) perpendicular to one another and perpendicular to the direction of wave propagation. D) perpendicular to one another and parallel to the direction of wave propagation
c
62) Except for their color, a perfectly black (absorbing) object is identical to a perfectly white (reflecting) object. If identical light falls on both of these objects, what is true about the momentum they will receive from this light? A) The black object will receive twice as much as the white object. B) They will both receive the same amount. C) The white object will receive twice as much as the black object. D) The black object will receive four times as much as the white object. E) The white object will receive four times as much as the black object.
c
64) If the index of refraction of a material is 2, this means that light travels A) 2 times as fast in air as it does in vacuum. B) 2 times as fast in the material as it does in air. C) 2 times as fast in vacuum as it does in the material. D) 2 times as fast in the material than it does in vacuum. E) 1/2 as fast in air as it does in the material.
c
66) Light enters glass from air. The angle of refraction will be A) greater than the angle of incidence. B) equal to the angle of incidence. C) less than the angle of incidence.
c
69) Which one of the following sets of characteristics describes the image formed by a plane mirror? A) real and inverted B) real and upright C) virtual and upright D) virtual and inverted E) virtual and larger than the object
c
70) The image formed in a plane mirror is A) at the same distance in front of the mirror as the object is in front of the mirror. B) a real image behind the mirror. C) at the same distance behind the mirror as the object is in front of the mirror. D) at a shorter distance behind the mirror than the distance the object is in front of the mirror. E) at a larger distance behind the mirror than the distance the object is in front of the mirror.
c
72) A lighted candle is placed a short distance from a plane mirror, as shown in the figure. At which location will the image of the flame appear to be located? A) at A B) at B C) at C D) at M (at the mirror)
c
8) A proton, moving north, enters a magnetic field. Because of this field, the proton curves downward. We may conclude that the magnetic field must have a component A) downward. B) upward. C) towards the east. D) towards the west. E) towards the north.
c
92) Is it possible to see a virtual image? A) No, since the rays that seem to emanate from a virtual image do not in fact emanate from the image. B) No, since virtual images do not really exist. C) Yes because the rays that appear to come from a virtual image can be focused by the eye just like those from an object. D) Yes, but only by using an additional lens to form a real image before the light reaches the eye
c
93) If a single lens forms a virtual image of an object, then A) the lens must be a diverging lens. B) the lens must be a converging lens. C) the lens could be either a diverging or a converging lens. D) the image must be inverted. E) the object must be between the lens and its focal point.
c
61) Which of the following statements about electromagnetic waves in free space are true? (There could be more than one correct choice.) A) The electric field carries more energy than the magnetic field. B) The electric and magnetic fields have equal amplitudes. C) The electric field carries the same mount of energy as the magnetic field. D) The frequency of the magnetic field is the same as the frequency of the electric field. E) The frequency of the electric field is higher than the frequency of the magnetic field.
cd
18) If a calculated quantity has units of ns/Cm , that quantity could be A) an electric field. B) an electric potential. C) μ0. D) a magnetic field. E) a magnetic torque.
d
20) We observe that a moving charged particle experiences no magnetic force. From this we can definitely conclude that A) no magnetic field exists in that region of space. B) the particle must be moving parallel to the magnetic field. C) the particle is moving at right angles to the magnetic field. D) either no magnetic field exists or the particle is moving parallel to the field. E) either no magnetic field exists or the particle is moving perpendicular to the field.
d
28) For the horseshoe magnet shown in the figure, the left end is a north magnetic pole and the right end is a south magnetic pole. When the switch is closed in the circuit, which way will the wire between the poles of the horseshoe magnet initially deflect? A) to the right B) to the left C) upward D) downward
d
30) Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in opposite directions, A) one wire is lifted slightly while the other wire is forced downward against the table's surface. B) both wires are lifted slightly. C) the wires pull toward each other. D) the wires push away from each other
d
34) A negatively charged particle -Q is moving to the right, directly above a wire having a current I flowing to the right, as shown in the figure. In what direction is the magnetic force exerted on the particle due to the current? A) into the page B) out of the page C) downward D) upward E) The magnetic force is zero because the velocity is parallel to the current.
d
35) A wire lying in the plane of the page carries a current toward the bottom of the page, as shown in the figure. What is the direction of the magnetic force it produces on an electron that is moving to the left directly toward the wire, as shown? A) straight into the page B) straight out of the page C) directly toward the top of the page D) directly toward the bottom of the page E) directly to the left away from the wire
d
45) A long straight wire lies on a horizontal table and carries an ever-increasing current toward the north. Two coils of wire lie flat on the table, one on either side of the wire. When viewed from above, the direction of the induced current in these coils is A) clockwise in both coils. B) counterclockwise in both coils. C) clockwise in the east coil and counterclockwise in the west coil. D) counterclockwise in the east coil and clockwise in the west coil.
d
54) Which one of the following is not an electromagnetic wave? A) ultraviolet B) infrared C) radio waves D) sound waves E) gamma rays
d
56) Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength? A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays B) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays D) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
d
7) An electron, moving south, enters a magnetic field. Because of this field, the electron curves upward. We may conclude that the magnetic field must have a component A) downward. B) towards the east. C) upward. D) towards the west. E) towards the north
d
73) Which one of the following numbers is the correct magnification produced by a plane mirror? A) 1/2 B) 1/4 C) 2 D) 1 E) 3/2
d
75) Suppose you place an object in front of a concave mirror. Which of the following statements must be true? (There could be more than one correct choice.) A) The image of the object will always be smaller than the object. B) No matter where you place the object, a real image of the object will be formed. C) The image of the object will always be inverted. D) If you position the object between the mirror and the focal point of the mirror, its image must be upright and virtual. E) No matter where you place the object, the image of the object will always be virtual and upright
d
77) A negative magnification for a mirror means that A) the image is inverted, and the mirror could be either concave or convex. B) the image is upright, and the mirror is convex. C) the image is inverted, and the mirror is convex. D) the image is inverted, and the mirror is concave. E) the image is upright, and the mirror could be either concave or convex.
d
79) An object is placed in front of a convex mirror at a distance larger than twice the magnitude of the focal length of the mirror. The image will appear A) in front of the mirror. B) inverted and reduced. C) inverted and enlarged. D) upright and reduced. E) upright and enlarged.
d
80) Single concave spherical mirrors produce images that A) are always smaller than the actual object. B) are always larger than the actual object. C) are always the same size as the actual object. D) could be smaller than, larger than, or the same size as the actual object, depending on the placement of the object. E) are always real.
d
82) A beam of light that is parallel to the principal axis strikes a concave mirror. What happens to the reflected beam of light? A) It also is parallel to the principal axis. B) It is perpendicular to the principal axis. C) It passes through the center of curvature of the mirror. D) It passes through the focal point of the mirror. E) It passes between the focal point and the center of curvature of the mirror.
d
84) Suppose you wanted to start a fire using a mirror to focus sunlight. Which of the following statements is most accurate? A) It would be best to use a plane mirror. B) It would be best to use a convex mirror. C) It would be best to use a concave mirror, with the object to be ignited positioned at the center of curvature of the mirror. D) It would be best to use a concave mirror, with the object to be ignited positioned halfway between the mirror and its center of curvature. E) One cannot start a fire using a mirror, since mirrors form only virtual images.
d
88) A convex lens has focal length f. If an object is placed at a distance between f and 2f from the lens on the principal axis, the image is located at a distance from the lens A) of 2f. B) between f and 2f. C) of f. D) that is greater than 2f. E) of infinity.
d
91) Starting from very far away, an object is moved closer and closer to a converging lens, eventually reaching the lens. What happens to its image formed by that lens? (There could be more than one correct choice.) A) The image gets closer and closer to the lens. B) The image gets farther and farther from the lens. C) The image eventually changes from virtual to real. D) The image eventually changes from real to virtual. E) The image keeps getting larger and larger.
d
94) Which statement about a single thin lens is correct? A) A converging lens always produces a real inverted image. B) A diverging lens always produces a virtual inverted image. C) A converging lens sometimes produces a real upright image. D) A diverging lens always produces a virtual upright image. E) A diverging lens produces a virtual upright image only if the object is located between the lens and its focal point.
d
95) When light travels from air into water, A) its velocity, wavelength and frequency all change. B) its velocity changes, but its frequency and wavelength do not change. C) its frequency changes, but its velocity and wavelength do not change. D) its velocity and wavelength change, but its frequency does not change. E) its wavelength changes, but its velocity and frequency do not change.
d
98) In a double-slit interference experiment you are asked to use laser light of different wavelengths and determine the separation between adjacent maxima. You observe that this separation is greatest when you illuminate the double slit with A) blue light. B) green light. C) yellow light. D) red light. E) The separation is the same for all wavelengths.
d
67) A beam of light traveling in air strikes a glass slab at an angle of incidence less than 90°. After entering the glass slab, what does the beam of light do? (There could be more than one correct choice.) A) I follows the same path as before it struck the glass. B) It follows the normal to the glass slab. C) It bends away from the normal at the point of contact. D) It bends closer to the normal at the point of contact. E) It slows down
de
78) An object is placed to the left of a spherical mirror in front of the mirror. If the image of the object is formed on the right side of the mirror, which of the following statements must be true? (There could be more than one correct choice.) A) The image is upright and the mirror must be convex. B) The image is inverted and real, and the mirror must be convex. C) The image is upright and the mirror must be concave. D) The image is upright and virtual. E) The mirror could be either concave or convex
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13) Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles? A) 1 is neutral, 2 is negative, and 3 is positive. B) 1 is neutral, 2 is positive, and 3 is negative. C) 1 is positive, 2 is neutral, and 3 is negative. D) 1 is positive, 2 is negative, and 3 is neutral. E) 1 is negative, 2 is neutral, and 3 is positive.
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14) An electron moving in the +y direction, at right angles to a magnetic field, experiences a magnetic force in the -x direction. The direction of the magnetic field is in the A) -x direction. B) +x direction. C) +y direction. D) -z direction. E) +z direction.
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17) A proton is to orbit Earth at the equator using Earth's magnetic field to supply part of the necessary centripetal force. In what direction should the proton move? A) upward B) northward C) southward D) eastward E) westward
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36) A long straight wire has a constant current flowing to the right. A rectangular metal loop is situated above the wire, and also has a constant current flowing through it, as shown in the figure. Which one of the following statements is true? A) The net magnetic force on the rectangle is upward, and there is also a nonzero torque on the rectangle. B) The net magnetic force on the rectangle is zero, and the net torque on it is zero. C) The net magnetic force on the rectangle is downward, and there is also a nonzero torque on the rectangle. D) The net magnetic force on the rectangle is zero, but there is a nonzero torque on the rectangle. E) The net magnetic force on the rectangle is downward, and the net torque on it is zero.
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4) A positive charge is moving to the right and experiences an upward magnetic force, as shown in the figure. In which direction must the magnetic field have a component? A) to the right B) to the left C) upward D) out of the page E) into the page
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59) Which one of the following types of electromagnetic wave travels through space the fastest? A) radio waves B) infrared C) ultraviolet D) microwaves E) They all travel through space at the same speed.
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60) The energy density of an electromagnetic wave in free space is A) entirely in the electric field. B) entirely in the magnetic field. C) 1/4 in the electric field and 3/4 in the magnetic field. D) 1/4 in the magnetic field and 3/4 in the electric field. E) equally divided between the magnetic and the electric fields.
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71) You may have seen ambulances on the street with the letters of the word AMBULANCE written on the front of them, in such a way as to appear correctly when viewed in your car's rear-view mirror. (See the figure.) How do the letters appear when you look directly at the ambulance (not through the mirror)? A) a B) b C) c D) d E) e
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74) As you walk away from a plane mirror on a wall, the height of your image A) gets smaller. B) may or may not get smaller, depending on where the observer is positioned. C) is always a real image, no matter how far you are from the mirror. D) changes from being a virtual image to a real image as you pass the focal point. E) is always the same size.
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