Final Exam Part 2  Nota means none of the above.

53. An ampere is a unit of 
a. time
b. pressure
c. charge 
d.  nota*
54. What is the effect  on the current in a wire if the resistance is doubled without changing the voltage across it? 
a. The current is doubled
b. The current is reduced by one half*
c. the current does not change.
d.  nota
55.What is the effect on the current in a wire if both the voltage across  it and the resistance are tripled? 
a. the current is tripled. 
b. the current is reduced by one third
c. nota*
56.  2 coulombs of charge pass through a 6-volt battery. Inside the battery, the charge gains  
a. 6 Joules of potential energy 
b. 12 Joules of potential energy*
57. A 10-ohm resistor has a 10-A current in it. What is the voltage across the resistor? 
a. 10 Volts
b. 20 Volts
c. 100  Volts*
58. In the previous problem, what is the rate of heat generation in the wire?
a. 100 Watts
b. 1000 Watts*
c. 10,000 Watts
d. nota
59. Two unequal  resistors are connected in series to a battery. The current is greater in the resistor with the 
a.  largest value
b. smallest value
c. the current is the same in each resistor*
60. Two unequal  resistors are connected in parallel  to a battery. The current is greater in the resistor with the 
a.  largest value
b. smallest value*
c. the current is the same in each resistor
61. Modern automobile headlights are connected in 
a. parallel*
b. series 
c. nota 
62. Two resistors, 1-ohm and  100 ohm, are connected in parallel to a battery. The equivalent resistance of the circuit is
a. greater than 100 ohms
b. less than 1 ohm*
c. nota
63. Two resistors, 1-ohm and  100 ohm, are connected in series to a battery. The equivalent resistance of the circuit is
a. greater than 100 ohms*
b. less than 1 ohm
c. nota
64. The source of all magnetism is
a. tiny pieces of iron
b. moving electric charge*
c. electric charge at rest
d. nota
65. True of False. A current in a conducting wire produces a magnetic field. 
a. True*
b. False
66. A conducting long straight wire  loop lies horizontally  in the plane of the page. A current flows leftward through the wire. What is the direction of the magnetic field directly above the wire?  (It would help if you sketched  the straight line and drew an arrow pointing left on the line representing the current.  Hint:  Use the right hand rule for long straight wires by pointing your right thumb leftward  in the direction of the current. Your right fingers will  point in the direction of the  magnetic field directly above the line.) 
a. in *
b. out
c. nota 
67. True or False.  A magnetic field exerts a  force on a charge at rest.
a. True
b. False*
68.  True or False.  The magnetic force on a charge moving in a magnetic field  is perpendicular to the velocity of the  particle.  
a. True*
b. False
69.  True or False.  The magnetic force on a  charge moving in a magnetic field  is perpendicular to the magnetic field.  
a. True*
b. False
70.  True or False.  The magnetic force on a straight,  current carrying wire in an external magnetic field  is perpendicular to the current.  
a. True*
b. False
71. True or False.  The magnetic force on a straight,  current carrying wire in an external magnetic field  is perpendicular to the magnetic field.   
a. True*
b. False
72.  2 long straight wires are  parallel and their currents flow in opposite directions. The two wires
a. attract each other
b. repel each other*
73.  True or False. The geographic south pole  of the Earth coincides with the Earth's   magnetic south pole.
a. True
b. False*
74. True or False. Magnetic field lines come out of the south pole  and enter the north pole of a magnet.   
a. True
b. False *
75. True or False. A length of wire is bent into a  closed loop and a magnet near the loop is at rest. The current in the loop is zero. 
a. True*
b. False
76. True or False. A length of wire is bent into a  closed loop and a magnet nearby is thrust (moved) into the loop. The current in the loop will be zero.
a. True
b. False*
77. A circular loop of copper wire is lying flat  on a horizontal table. A bar magnet is held with its North pole downward vertically above the center of the coil. The magnet is released from rest and falls toward the coil. As viewed from above, as it falls,  the magnet induces 
a.  a counter-clockwise current in the loop* 
b. a clockwise current in the loop
78. According to Faraday's Law, a current flows in a loop of wire  when there is a change in
a. the electric field intensity through  the loop.
b. the magnetic field intensity through the loop.*
79. A device that transforms mechanical energy into electrical  energy is a 
a. generator*
b. motor
c. transformer
d. nota
80.  A device that transforms electrical energy into mechanical  energy is a 
a. generator
b. motor*
c. transformer
d. nota
 81. Neon signs require about 12,000 volts (output voltage) to operate. The "step up"  transformer circuit uses a 120-Volt (input voltage) source.  What is the ratio of primary to secondary turns on the transformer?
a. 1/100* 
b. 100/1
c. nota
82. True or False. Most of the waves in the electromagnetic spectrum are visible to the naked eye. 
a. True
b. False*
83. The main difference between  x-ray waves and  micro-waves in a vacuum is the 
a. wave speed
b. wavelength*
84. Which of these waves has the  largest frequency?
a. radio waves
b. infrared waves
c. X-Rays*
d. ultraviolet waves
e. light waves
85. Which of these waves has the shortest wavelength?
a. light waves
b. radio waves
c. x-rays
d. gamma rays*
86. Which does not require a physical medium in which to travel?
a. infra-red  waves*
b. sound waves
87. Extra Credit. The natural frequency of vibrating electrons in atoms of glass is in the 
a. infrared part of the spectrum
b. visible part of the spectrum
c. ultraviolet part of the spectrum*
88. Extra Credit. The speed of light in the space  between molecules in glass is 
a. more than its speed in a vacuum
b. less than its speed in a vacuum
c. the same as its speed in a vacuum*
89. Extra Credit. Compared to  its speed in a vacuum, the average speed of a beam of light in glass is 
a. more
b. less*
c. the same
Extra Credit Chapter 31
90. The frequency  of red  light is about half that of violet light. How does the energy E of a red  photon compare with the energy of a violet photon?
a. The energy is twice  the energy  of a violet photon
b. The energy is one half the energy of a violet photon*
c. same energy
91. The photoelectric effect best illustrates the 
a. wave nature of light
b. particle nature of light*
c. nota
92. In the photoelectric effect, the brighter the illuminating light on the photosensitive surface, the greater the
a. number of ejected electrons*
b. kinetic energy of ejected electrons
c. nota
93.  Does the DeBroglie wavelength  of an electron become longer or shorter as the momentum decreases ?
a. longer*
b. shorter
c. remains the same