MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) An originally neutral electroscope is grounded briefly while a negatively charged rod is held near it. After the rod is removed, the electroscope
A) could be either positively or negatively charged, depending on how long the contact with ground lasted. B) remains neutral. C) is positively charged. D) is negatively charged.
2) Sphere A carries a net charge and spheres B and C are neutral. They are placed near each other on an insulated table. Which statement best describes the electrostatic force between them?
A) There is no force between them since two are neutral. B) There is a force of repulsion between all of them. C) A attracts B and A attracts C, but B and C show no attraction. D) There is a force of attraction between all of them.
3) Two charged objects attract each other with a force F. What happens to the force between them if both charges are doubled, and the separation distance between their centers is reduced to one-fourth its original value? The force is now equal to
A) (3/8)F. B) 16F. C) 96F. D) 64F.
4) A negatively charged rod is brought near one end of an uncharged metal bar. The end of the metal bar closest to the negatively charged rod will be charged
A) negative. B) positive. C) neutral. D) none of the given answers
5) A point charge of +Q is placed at the center of a square. When a second point charge of -Q is placed at one of the square's corners, it is observed that an electrostatic force of 2.0 N acts on the positive charge at the square's center. Now, identical charges of +Q are placed at the other three corners of the square. What is the magnitude of the net electrostatic force acting on the positive charge at the center of the square?
A) 2.8 N B) zero C) 4.0 N D) 8.0 N
6) A 1.0 nC (nC = 10^-9 Coulomb) charge is 15 m from a second charge, and the force between them is 1.0 N. What is the magnitude of the second charge?
A) 1.0 C B) 25 C C) 25 nC D) 0.025 C
7) Three point charges are located at the following positions: Q1 = 2.00 x 10^-5 C at x = 1.00 m; Q2 = 3.00 x 10^-5 C at x = 0; Q3 = -5.00 x 10^-5C at x = -1.00 m. What is the magnitude of the force on Q1?
A) 3.15 N B) 8.15 x10^-2 N C) 5.40 x 10^-2 N D) 2.25 x 10^-2 N
8) Q1 = 6.0 nC is at (0.30 m, 0); Q2 = -1.0 nC is at (0, 0.10 m); Q3 = -5.0 nC is at (0, 0). What is the direction of the net force on the -5.0 nC charge?
A) 34 degrees below -x axis B) 56 degrees below -x axis C) 34 degrees below +x axis D) 56 degrees below +x axis
9) Consider point charges of -Q and +4Q, which are separated by 3.0 m. At what point, on a line between the two charges, would it be possible to place a charge of -Q such that the electrostatic force acting on it would be zero?
A) There is no such point possible. B) 1.0 m from the +4Q charge C) 1.0 m from the -Q charge D) 0.60 m from the -Q charge
10) One (Amp)(Ohm) is a
A) farad. B) volt. C) newton. D) electron-volt.
11) One (coulomb)^2 per Joule is a(n)
A) electron-volt. B) watt. C) farad. D) joule.
12) A dielectric material such as paper is removed from between the plates of a capacitor. What happens to the capacitance?
A) no change B) becomes infinite C) becomes smaller D) becomes larger
13) What is 1 Watt equivalent to?
A) 1 V/A B) 1 J/s C) 1 W/A D) 1 VA
14) A coulomb per volt is the same as
A) a watt. B) a farad C) an ampere. D) a volt-second.
15) If the resistance in a constant voltage circuit is cut in half, the power dissipated by that circuit will
A) decrease to one-half its original value. B) decrease to one-fourth its original value. C) increase by a factor of four. D) increase by a factor of two.
16) If the resistance in a circuit with constant current flowing is cut in half, the power dissipated by that circuit will
A) decrease to one fourth. B) quadruple. C) decrease to one half. D) double.
17) What current is flowing if 4.0 x 10^18 electrons pass a point in 0.50 s?
A) 0.013 A B) 6.3 A C) 1.3 A D) 78 A
18) A 110-V hair dryer is rated at 1320 W. What current will it draw?
A) 1.0 A B) 12 A C) 11 A D) 0.090 A
19) A 200-Ohm resistor is rated at 1 W. What is the maximum current it can draw?
A) 50 A B) 0.25 A C) 0.035 A D) 0.071 A
20) 14 A of current flows through an 8.0 Ohm resistor for 12 hours. How much does this cost if energy costs $0.09/kWh?
A) $1.04 B) $0.24 C) $3.39 D) $1.70
21) As more resistors are added in parallel to a constant voltage source, the power supplied by the source
A) decreases. B) increases. C) does not change. D) increases for a time and then starts to decrease.
22) As more resistors are added in parallel to a constant voltage source, the current supplied by the source
A) increases for a time and then starts to decrease. B) increases. C) does not change. D) decreases.
23) A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. When this system reaches its steady-state (after a very very long time), the current through the resistor is
A) equal to the battery's terminal voltage. B) less than the battery's terminal voltage, but greater than zero. C) zero. D) greater than the battery's terminal voltage.
24) Four resistors of 12, 3.0, 5.0, and 4.0 Ohms are connected in series. A 24-V battery is connected to the combination. What is the current through the battery?
A) 1.5 A B) 2.0 A C) 1.0 A D) 0.50 A
25) A 14-A current flows into a series combination of a 3.0 Ohm and a 4.0 Ohm resistor. What is the voltage drop across the 3.0 Ohm resistor?
A) 56 V B) 98 V C) 38 V D) 42 V
26) A 22-A current flows into a parallel combination of a 4.0 Ohm, 6.0 Ohm, and 12 Ohm resistors. What current flows through the 4.0 Ohm resistor?
A) 3.7 A B) 7.3 A C) 18 A D) 11 A
27) A combination of resistors of 2.0 Ohms in series with 4.0 Ohms is connected in parallel with 6.0 ohms. What is the equivalent resistance?
A) 2.0 Ohms B) 4.0 Ohms C) 3.0 Ohms D) 9.0 Ohms
28) Three resistors of 4.0, 6.0, and 12.0 Ohms are connected in parallel. If the combination is connected in series with a 12.0-V battery and a 2.0 Ohm resistor, what is the current through the 2.0 Ohm resistor?
A) 16.0 A B) 0.59 A C) 11.2 A D) 3.0 A
29) A charged particle moves and experiences a maximum magnetic force. From this we can conclude that
A) the particle is moving at right angles to the magnetic field. B) no magnetic field exists in that region of space. C) either no magnetic field exists or the particle is moving parallel to the field. D) the particle is moving parallel to the magnetic field.
30) A charged particle moves perpendicular to a constant magnetic field. The magnetic force on this particle
A) causes the particle to change its direction B) is in the direction of the particle's motion. C) changes the particle's speed. D) changes the particle's speed causing the particle to accelerate.
31) A proton moving along the +x axis enters a region where there is a uniform magnetic field in the +y direction. What is the direction of the magnetic force on the proton? (+x to right, +y up, and +z out of the page.)
A) +z direction B) -z direction C) -x direction D) -y direction
32) A wire lying in the plane of the page carries a current toward the bottom of the page. What is the direction of the magnetic force it produces on a proton that is moving perpendicularly toward the wire, also in the plane of the page, from your right?
A) perpendicular to the page and towards you B) toward the top of the page C) perpendicular to the page and away from you D) zero E) toward the bottom of the page
33) An electron traveling due north with speed 8.0 x 10^5 m/s enters a region where the Earth's magnetic field has the magnitude 5.0 x10^-5 T and is directed downward at 45degree below horizontal. What force acts on the electron?
A) 2.3 x 10^-19 N B) 2.3 x 10^-18 N C) 3.2 x 10^-19 N D) 4.6 x 10^-18 N
34) How much current must flow for 1.0 x 10^-3 T of magnetic field to be present at a point 0.50 cm from a wire?
A) 0.050 A B) 50 A C) 25 A D) 9.2 A
35) In a mass spectrometer, a single-charged particle (charge e) has a speed of 1.0 x 10^6 m/s and enters a uniform magnetic field of 0.20 T. The radius of the circular orbit is 0.010 m. What is the mass of the particle?
A) 1.7 x 10^-27 kg B) 3.2 x 10^-28 kg C) 6.4 x 10^-28 kg D) 3.1 x 10^-31 kg
36) An image formed when the light rays appear to come from an image location, but cannot appear on paper or film placed at the that location is referred to as a
A) real image. B) virtual image.
37) A spherical mirror on which reflection takes place on the inner surface of the spherical shape is referred to as a
A) convex mirror. B) concave mirror.
38) A light ray is traveling in towards a concave mirror through its focal point. After reflection, this ray
A) passes through the mirror's center of curvature. B) travels at right angles to the mirror's axis. C) travels parallel to the mirror's axis. D) passes through the mirror's focal point.
39) If you stand in front of a concave mirror, exactly at its center of curvature,
A) you will see your image and you will appear larger. B) you won't see your image because it's focused at a different distance. C) you will see your image at your same height. D) you will see your image, and you will appear smaller. E) you won't see your image because there is none.
40) Concave spherical mirrors produce images which
A) are always the same size as the actual object. B) are always larger than the actual object. C) could be larger than, smaller than, or the same size as the actual object, depending on the placement of the object. D) are always smaller than the actual object.
41) Light enters glass from water. The angle of refraction will be
A) less than the angle of incidence. B) greater than the angle of incidence. C) equal to the angle of incidence.
42) A convex lens has a focal length f. An object is placed beyond 2f on the axis. The image formed is located
A) between f and 2f. B) at 2f. C) at a distance greater than 2f from the lens. D) at f.
43) An object is placed 15 cm from a concave mirror of focal length 20 cm. The object is 2.0 cm tall. How tall is the image?
A) 8.0 cm B) 2.0 cm C) 1.0 cm D) 16 cm
44) When a person stands 40 cm in front of a shaving mirror (concave mirror), the right-side-up image is twice the size of the object. What is the focal length of the mirror?
A) 80 cm B) 27 cm C) 160 cm D) 40 cm
45) An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day. What is the angle of refraction in the air for a ray of light that has an angle of incidence of 32degrees as it enters the oil from the water below? (The index of refraction for oil is 1.15, and for water it is 1.33.)
A) 45degrees B) 36degrees C) 32degrees D) 27degrees
46) Light enters a substance from air at 30.0degrees to the normal. It continues through the substance at 23.0degrees to the normal. If it exists, what would be the critical angle for this substance?
A) It doesn't exist B) 53degrees C) 36.7degrees D) 51.4degrees
47) When an object is 40 m in front of a converging lens the inverted image is the same size as the object. What is the focal length of this lens?
A) 40 cm B) 13 cm C) 20 cm D) 53 cm
48) An object is 10.4 cm tall, and 4.8 cm in front of a diverging lens. The image is 4.0 cm from the lens. What kind of image is it, and how tall is the image?
A) virtual, 5.4 cm B) real, 1.8 cm C) real, 13 cm D) virtual, 8.7 cm
49) Three identical resistors are connected in parallel to a 12-V battery. What is the voltage across any one of the resistors?
A) 36 V B) 4 V C) zero D) 12 V
50) Three identical resistors are connected in parallel to a battery. If the current of 12 A flows from the battery, how much current flows through any one of the resistors?
A) zero B) 36 A C) 4 A D) 12 A