Physics Final Exam Study Guide 1
Physics NCFE Review
____ 1. A hypothesis is
|a. |the long side of a right triangle. |
|b. |an educated guess that has yet to be proven by experiment. |
|c. |close agreement by competent observers of observations of the same phenomena. |
|d. |a guess that has been tested over and over again and always found to be true. |
|e. |a synthesis of a large collection of information that includes guesses. |
____ 2. Speed is
|a. |a measure of how fast something is moving. |
|b. |always measured in terms of a unit of distance divided by a unit of time. |
|c. |the distance covered per unit time. |
|d. |all of the above. |
|e. |none of the above. |
____ 3. If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first?
|a. |The feather |
|b. |Neither—they will both reach the bottom at the same time. |
|c. |The coin |
____ 4. Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration?
|a. |5 km/h·s |
|b. |10 km/h·s |
|c. |35 km/h·s |
|d. |40 km/h·s |
|e. |45 km/h·s |
____ 5. A ball is thrown straight up. At the top of its path its instantaneous speed is
|a. |0 m/s. |
|b. |about 5 m/s. |
|c. |about 10 m/s. |
|d. |about 20 m/s. |
|e. |about 50 m/s. |
____ 6. A freely falling object starts from rest. After falling for 6 seconds, it will have a speed of about
|a. |6 m/s. |
|b. |30 m/s. |
|c. |60 m/s. |
|d. |300 m/s. |
|e. |more than 300 m/s. |
____ 7. Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of
|a. |1 m. |
|b. |2 m. |
|c. |3 m. |
|d. |4 m. |
|e. |5 m. |
____ 8. A vector is a quantity that has
|a. |magnitude and time. |
|b. |time and direction. |
|c. |magnitude and direction. |
____ 9. A scalar is a quantity that has
|a. |direction. |
|b. |magnitude. |
|c. |time. |
|d. |color. |
____ 10. Which of the following would NOT be considered a projectile?
|a. |A cannonball thrown straight up |
|b. |A cannonball rolling down a slope |
|c. |A cannonball rolling off the edge of a table |
|d. |A cannonball thrown through the air |
|e. |All of the above are projectiles. |
____ 11. A ball thrown in the air will never go as far as physics ideally would predict because
|a. |one can never throw the ball fast enough. |
|b. |gravity is acting. |
|c. |air friction slows the ball. |
|d. |ideally the ball would never land. |
|e. |all of the above |
____ 12. A projectile launched horizontally hits the ground in 0.8 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting Earth's curvature and air resistance) in
|a. |more than 0.8 s. |
|b. |0.8 s. |
|c. |less than 0.8 s. |
____ 13. A projectile is fired horizontally in a vacuum. The projectile maintains its horizontal component of speed because it
|a. |has no vertical component of speed to begin with. |
|b. |is not acted on by any forces. |
|c. |the net force acting on it is zero. |
|d. |is not acted on by any horizontal forces. |
|e. |none of the above |
____ 14. Which best approximates the resultant of a pair of 6-unit vectors at right angles to each other?
|a. |0 units. |
|b. |6 units. |
|c. |8 units. |
|d. |12 units. |
____ 15. A cannonball is fired at some angle into the air. In the first second it moves 5 meters horizontally. Assuming it doesn't hit the ground and air resistance is negligible, how far does it move horizontally in the next second?
|a. |More than 5 m |
|b. |Less than 5 m |
|c. |5 m |
|d. |Not enough information. |
____ 16. A cannon with a barrel velocity of 140 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, how far vertically will the cannonball have fallen after 4 seconds?
|a. |80 m |
|b. |140 m |
|c. |560 m |
|d. |2240 m |
|e. |none of the above |
____ 18. If the force of gravity suddenly stopped acting on the planets, they would
|a. |spiral slowly towards the sun. |
|b. |continue to orbit the sun. |
|c. |move in straight lines tangent to their orbits. |
|d. |spiral slowly away from the sun. |
|e. |fly straight away from the sun. |
____ 19. Compared to its mass on Earth, the mass of a 10-kg object on the moon is
|a. |the same. |
|b. |more. |
|c. |less. |
____ 20. You would have the largest mass of gold if your chunk of gold weighed 1 N on
|a. |Earth. |
|b. |Jupiter. |
|c. |the moon. |
____ 21. Friction is a force that always acts
|a. |perpendicular to an object's motion. |
|b. |opposite to an object's motion. |
|c. |in the same direction as an object's motion. |
____ 22. What is the minimum resultant possible when adding a 5-N force to an 8-N force?
|a. |5 N |
|b. |3 N |
|c. |8 N |
|d. |13 N |
|e. |40 N |
____ 23. An apple weighs 1 N. The net force on the apple when it is in free fall is
|a. |0 N. |
|b. |0.1 N. |
|c. |1 N. |
|d. |9.8 N. |
|e. |none of the above |
____ 24. A box is dragged without acceleration in a straight-line path across a level surface by a force of 13 N. What is the frictional force between the box and the surface?
|a. |13 N |
|b. |Less than 13 N |
|c. |More than 13 N |
|d. |Need more information to say. |
____ 25. Which of the following would exert the most pressure on the ground?
|a. |A woman standing in running shoes |
|b. |A woman standing on skis |
|c. |A woman standing in high-heel shoes |
____ 26. If the force acting on a cart doubles, what happens to the cart's acceleration?
|a. |It quarters. |
|b. |It halves. |
|c. |It stays the same. |
|d. |It doubles. |
|e. |It quadruples. |
____ 27. Suppose a cart is being moved by a force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration?
|a. |It quarters. |
|b. |It halves. |
|c. |It stays the same. |
|d. |It doubles. |
|e. |It quadruples. |
____ 28. A player hits a ball with a bat. The action force is the impact of the bat against the ball. What is the reaction to this force?
|a. |The force of the ball against the bat |
|b. |The weight of the ball |
|c. |Air resistance on the ball |
|d. |The grip of the player's hand against the bat |
|e. |none of the above |
____ 29. A person is attracted towards the center of Earth by a 440-N gravitational force. The force with which Earth is attracted toward the person is
|a. |440 N. |
|b. |very very small. |
|c. |very very large. |
____ 30. An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is
|a. |larger. |
|b. |the same. |
|c. |smaller. |
|d. |Need more information to say |
____ 31. If a horse pulls on a wagon at rest, the wagon pulls back equally on the horse. Can the wagon be set into motion?
|a. |Yes, because there is a net force acting on the wagon. |
|b. |Yes, because there is a time delay between action and reaction. |
|c. |No, because the forces cancel each other. |
|d. |Yes, because the horse's pull on the wagon is larger than the wagon's pull on the horse. |
____ 32. According to Newton's third law, if you push gently on something, it will push
|a. |gently on something else. |
|b. |on you only if you aren't moving. |
|c. |gently on you. |
|d. |on something only under the right conditions. |
____ 33. Earth pulls on the moon, and similarly the moon pulls on Earth. This is evidence that the
|a. |Earth and moon are simply pulling on each other. |
|b. |Earth's and moon's pulls comprise an action-reaction pair. |
|c. |both a and b |
|d. |neither a or b |
____ 34. As a 600-N woman sits on the floor, the floor exerts a force on her of
|a. |6 N. |
|b. |60 N. |
|c. |1200 N. |
|d. |600 N. |
|e. |6000 N. |
____ 35. Suppose two people, one having three times the mass of the other, pull on opposite sides of a 20-meter rope while on frictionless ice. After a brief time, they meet. The more massive person slides a distance of
|a. |4 m. |
|b. |5 m. |
|c. |6 m. |
|d. |7 m. |
____ 36. The momentum change of an object is equal to the
|a. |impulse acting on it. |
|b. |velocity change of the object. |
|c. |force acting on it. |
|d. |force acting on it times its velocity. |
|e. |object's mass times the force acting on it. |
____ 37. In order to increase the final momentum of a golf ball, we could
|a. |increase the force acting on it. |
|b. |follow through when hitting the ball. |
|c. |increase the time of contact with the ball. |
|d. |swing as hard as possible. |
|e. |all of the above |
____ 38. The reason padded dashboards are used in cars is that they
|a. |look nice and feel good. |
|b. |decrease the impulse in a collision. |
|c. |increase the force of impact in a collision. |
|d. |decrease the momentum of a collision. |
|e. |increase the time of impact in a collision. |
____ 39. A table tennis ball launcher is fired. Compared to the force on the ball, the force on the launcher is
|a. |larger. |
|b. |the same. |
|c. |smaller. |
____ 40. A table tennis ball launcher is fired. Compared to the impulse on the ball, the impulse on the launcher is
|a. |smaller. |
|b. |larger. |
|c. |the same. |
____ 41. A collision is considered elastic if
|a. |there is no lasting deformation. |
|b. |the objects don’t stick together. |
|c. |the objects that collide don't get warmer. |
|d. |after the collision, the objects have the same shape as before the collision. |
|e. |all of the above |
____ 42. A cannon fires a cannonball. The speed of the cannonball will be the same as the speed of the recoiling cannon
|a. |if the mass of the cannonball equals the mass of the cannon. |
|b. |because momentum is conserved. |
|c. |because velocity is conserved. |
|d. |because both velocity and momentum are conserved. |
|e. |none of the above |
____ 43. The force of an apple hitting the ground depends upon
|a. |the speed of the apple just before it hits. |
|b. |the time of impact with the ground. |
|c. |whether or not the apple bounces. |
|d. |air resistance on the apple as it falls. |
|e. |all of the above |
____ 44. When you jump off a step, you usually bend your knees as you reach the ground. By doing this, the time of the impact is about 10 times more what it would be in a stiff-legged landing, and the average force on your body is reduced by
|a. |less than 10 times. |
|b. |about 10 times. |
|c. |more than 10 times. |
____ 45. Suppose an astronaut in outer space wishes to toss a ball against a very massive and perfectly elastic concrete wall and catch it as it bounces back. If the ball is as massive as the astronaut, then
|a. |the astronaut's time between catches will decrease as the game progresses. |
|b. |the astronaut will never catch the first bounce. |
|c. |the astronaut will catch one bounce only. |
|d. |none of the above |
____ 46. If Nellie Newton pushes an object with twice the force for twice the distance, she does
|a. |twice the work. |
|b. |the same work. |
|c. |four times the work. |
|d. |eight times the work. |
____ 47. The unit of work is the
|a. |watt. |
|b. |meter. |
|c. |joule. |
|d. |newton. |
|e. |second. |
____ 48. The unit of power is the
|a. |newton. |
|b. |meter. |
|c. |joule. |
|d. |second. |
|e. |watt. |
____ 49. A woman can lift barrels a vertical distance of 1 meter or can roll them up a 2-meter long ramp to the same elevation. If she uses the ramp, the applied force required is
|a. |[pic] as much. |
|b. |[pic] as much. |
|c. |the same amount. |
|d. |2 times as much. |
|e. |4 times as much. |
____ 50. A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
|a. |energy. |
|b. |power. |
|c. |both A and B |
|d. |none of the above |
____ 51. A person on a roof throws one ball downward and an identical ball upward at the same speed. The ball thrown downward hits the ground with 140 J of kinetic energy. Ignoring air friction, with how much kinetic energy does the second ball hit the ground?
|a. |less than 140 J |
|b. |140 J |
|c. |280 J |
|d. |more than 280 J |
|e. |none of the above |
____ 52. An object at rest may have
|a. |energy. |
|b. |speed. |
|c. |velocity. |
|d. |momentum. |
|e. |none of the above |
____ 53. All simple machines ideally work on the principle that
|a. |impulse equals momentum change. |
|b. |force equals mass times acceleration. |
|c. |total momentum before a collision equals total momentum after the collision. |
|d. |work input equals work output. |
|e. |kinetic energy transforms into potential energy. |
____ 54. How much work is done on a 20-N crate that you lift 2 m?
|a. |0 J |
|b. |1 J |
|c. |2 J |
|d. |20 J |
|e. |40 J |
____ 55. Suppose a moving car has 3000 J of kinetic energy. If the car's speed doubles, how much kinetic energy will it then have?
|a. |1000 J |
|b. |1500 J |
|c. |3000 J |
|d. |6000 J |
|e. |12,000 J |
____ 56. If Kelly the skater's speed increases so he has three times the momentum, then his kinetic energy increases by
|a. |one third times. |
|b. |three times. |
|c. |nine times. |
|d. |none of the above (KE remains the same). |
____ 57. Sue can easily lift a 45.0-N rock with the help of a lever. When she pushes down with 20.0 N of force, she lifts the rock 0.3 meters. How far does she move her arms to do this?
|a. |0.3 m |
|b. |0.7 m |
|c. |6.0 m |
|d. |2.3 m |
|e. |20.0 m |
____ 58. A frictionless inclined plane is 8.0 m long and rests on a wall that is 2.0 m high. How much force is needed to push a block of ice weighing 300.0 N up the plane?
|a. |37.5 N |
|b. |75.0 N |
|c. |100.0 N |
|d. |300.0 N |
|e. |600.0 N |
____ 59. A certain jack has a theoretical mechanical advantage of 300. However, due to frictional forces, the actual mechanical advantage is only 100. What is the efficiency of the jack?
|a. |[pic] |
|b. |[pic] |
|c. |30 |
|d. |300 |
|e. |30,000 |
____ 60. A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is
|a. |10%. |
|b. |50%. |
|c. |90%. |
|d. |110%. |
|e. |none of the above |
____ 61. If you whirl a tin can on the end of a string and the string suddenly breaks, the can will
|a. |fly directly away from you. |
|b. |fly off, tangent to its circular path. |
|c. |fly directly toward you. |
|d. |spiral in toward your hand. |
|e. |spiral away from your hand. |
____ 62. A person weighs less at the equator than at the poles. The reason for this has to do with the
|a. |tidal bulges. |
|b. |influence of the sun, moon, and all the planets. |
|c. |higher temperature at the equator, and expansion of matter. |
|d. |spin of the Earth. |
|e. |none of the above |
____ 63. To weigh less in the Northern Hemisphere, you should go
|a. |west. |
|b. |east. |
|c. |south. |
|d. |north. |
____ 64. Where is the center of gravity of a softball bat located?
|a. |Exactly halfway along the bat |
|b. |In the thin handle |
|c. |In the more massive end of the bat |
____ 65. When you carry a heavy load with one arm, why do you tend to hold your free arm away from your body?
|a. |To change the mass of your body |
|b. |To be ready to grab something in case you fall |
|c. |To look good |
|d. |To change the center of gravity of your body and the load |
|e. |To change the weight of your body and the load |
____ 66. Any solid cylinder will roll down an incline with greater acceleration than any hollow cylinder if the _____.
|a. |diameter of the solid cylinder is large |
|b. |mass of the solid cylinder is small |
|c. |mass of the solid cylinder is large |
|d. |none of the above are necessary |
____ 67. An object will maintain its angular momentum unless acted on by an unbalanced force.
|a. |Always true |
|b. |Sometimes true |
|c. |Always false |
____ 68. If the mass of Earth increased, with no change in radius, your weight would _____.
|a. |stay the same |
|b. |decrease |
|c. |increase also |
|c. |Both forces are the same. |
____ 69. The force of gravity acting on you will increase if you _____.
|a. |stand on a planet with a radius that is shrinking |
|b. |burrow deep inside the planet |
|c. |both A and B |
|d. |none of the above |
|e. |all of the above |
____ 70. If the mass of Earth increased, with no change in radius, your weight would _____.
|a. |increase also |
|b. |stay the same |
|c. |decrease |
____ 71. If the radius of Earth were one half what it is now, and the mass were the same, what would be the value of g?
|a. |0 m/s2 |
|b. |4.9 m/s2 |
|c. |9.8 m/s2 |
|d. |19.6 m/s2 |
|e. |39.2 m/s2 |
____ 72. An object dropped from rest almost infinitely far from Earth falls to Earth because of Earth's gravitational field, and strikes the surface with a speed of about _____.
|a. |8 km/s |
|b. |9.8 m/s |
|c. |11 km/s |
|d. |none of the above |
____ 73. The frequency of a light source doubles as the light approaches you. As the same light source moves away from you at the same speed, its frequency _____.
|a. |is doubled |b. |is halved |c. |stays the same |
____ 74. A friend is riding on the back of a truck that is going away from you at 25 km/hr. After the truck passes, your friend throws a ball toward you at 55 km/h relative to her. How fast is the ball going relative to you?
|a. |25 km/h |
|b. |30 km/h |
|c. |55 km/h |
|d. |80 km/h |
|e. |105 km/h |
____ 75. A woman standing on the ground sees a rocket ship move past her at 95% the speed of light. Compared to the rocket at rest, the woman sees the rocket's length as
|a. |longer. |
|b. |the same. |
|c. |shorter. |
____ 76. The charge on an atom that has one less electron than protons is _____.
|a. |neutral |
|b. |negative |
|c. |positive |
____ 77. Suppose a stone weighs 8 N in the air, but in water it weighs only 5 N. What is the buoyant force acting on the stone?
|a. |3 N |
|b. |5 N |
|c. |8 N |
|d. |13 N |
|e. |16 N |
____ 78. One liter of water weighs about 10 N. Suppose a 3-liter container is filled with 266 N of mercury and then lowered into a container of water. Assuming the container is completely submerged, what is the buoyant force acting on it?
|a. |30 N |
|b. |266 N |
|c. |27 N |
|d. |89 N |
|e. |10 N |
____ 79. A 40,000-N car is lifted on a hydraulic piston of area 1000 square centimeters. How much force on a 10 square-centimeter piston is needed to lift the car?
|a. |40,000 N |
|b. |10,000 N |
|c. |8,000 N |
|d. |4,000 N |
|e. |400 N |
____ 80. Heat is the _____.
|a. |average amount of energy per molecule contained in an object |
|b. |total amount of energy contained in an object |
|c. |energy transferred between objects because of a temperature difference |
|d. |amount of energy all the molecules have |
|e. |all of the above |
____ 81. Two like charges
|a. |neutralize each other. |
|b. |repel each other. |
|c. |must be neutrons. |
|d. |attract each other. |
|e. |have no effect on each other. |
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____ 82. Electrical forces between charges are strongest when the charges are
|a. |far apart. |
|b. |close together. |
|c. |The electrical force is constant everywhere. |
____ 83. A positive ion has
|a. |more electrons than protons. |
|b. |more protons than electrons. |
|c. |a +1 charge always. |
|d. |one proton. |
____ 84. To say that electric charge is conserved means that no case has ever been found where
|a. |the total amount of charge on an object has increased. |
|b. |one object has more charge than another object. |
|c. |the total charge on an object has changed. |
|d. |net charge has been created or destroyed. |
|e. |none of the above |
____ 85. In a good insulator, electrons are usually
|a. |not moving at all. |
|b. |free to move around after an impurity has been added. |
|c. |free to move around. |
|d. |tightly bound in place. |
|e. |semi-free to move around. |
____ 86. Charge carriers in a metal are electrons rather than protons, because electrons are
|a. |relatively far from a nucleus. |
|b. |loosely bound. |
|c. |lighter. |
|d. |all of the above |
|e. |none of the above |
____ 87. To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with
|a. |steel. |
|b. |wood. |
|c. |either A or B. |
____ 88. A conductor differs from an insulator in that a conductor has
|a. |more protons than electrons. |
|b. |faster-moving molecules. |
|c. |more electrons than protons. |
|d. |more electrons than an insulator. |
|e. |none of the above |
____ 89. Much electronic equipment contains transistors and diodes that are made from semiconductors. Semiconductors
|a. |can be very good insulators. |
|b. |can conduct electricity. |
|c. |contain helpful impurities. |
|d. |all of the above |
|e. |none of the above |
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____ 90. An electroscope is charged positively, as shown by foil leaves that stand apart. As a negatively charged rod is brought close to the electroscope, the leaves
|a. |spread farther apart. |
|b. |do not move. |
|c. |move closer together. |
____ 91. To charge an object by induction, the process of grounding
|a. |may or may not occur. |
|b. |always occurs. |
____ 92. When a charged cloud passes overhead, the ground below is charged by
|a. |induction. |
|b. |polarization. |
|c. |deduction. |
|d. |electrification. |
____ 93. Electrical polarization occurs when
|a. |an electron is at a different location than a proton. |
|b. |charge distribution in a neutral molecule separates. |
|c. |the electron and the proton are on different sides of an atom. |
|d. |an atom vibrates in a single direction. |
|e. |none of the above |
____ 94. The charge distribution in some molecules is permanently separated into positive and negative regions. Such molecules are called
|a. |ionized molecules. |
|b. |electric dipoles. |
|c. |coulomb molecules. |
|d. |induced molecules. |
|e. |insulators. |
____ 95. Two charged particles held close to each other are released. As the particles move, the velocity of each increases. Therefore, the particles have
|a. |the same sign. |
|b. |opposite signs. |
|c. |charges that cannot be determined. |
____ 96. A positive charge and a negative charge held near each other are released. As they move, the force on each particle
|a. |increases. |
|b. |stays the same. |
|c. |decreases. |
____ 97. Particle A has twice as much charge as particle B. Compared to the force on particle A, the force on particle B is
|a. |half as much. |
|b. |two times as much. |
|c. |four times as much. |
|d. |the same. |
|e. |none of the above |
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____ 98. Two charges separated by a distance of 1 meter exert a 20-N force on each other. If the charges are pulled to a 2 meter separation distance, the force on each charge will be
|a. |0 N. |
|b. |5 N. |
|c. |10 N. |
|d. |40 N. |
|e. |80 N. |
____ 99. Two charges separated by a distance of 1 meter exert a 2-N force on each other. If the magnitude of each charge is doubled, the force on each charge is
|a. |2 N. |
|b. |4 N. |
|c. |8 N. |
|d. |16 N. |
|e. |none of the above |
____ 100. Every proton in the universe is surrounded by its own
|a. |gravitational field. |
|b. |electric field. |
|c. |both A and B |
|d. |none of the above |
____ 101. The direction of electric field lines shows the
|a. |direction of the force on a test positive charge. |
|b. |size of the field. |
|c. |strength of the field. |
|d. |all of the above |
____ 102. Electrical potential energy is the energy a charged object has because of its
|a. |momentum. |
|b. |location. |
|c. |mass. |
|d. |motion. |
|e. |volume. |
____ 103. Suppose a hollow metal sphere has a large number of extra electrons on it. The extra electrons will be located
|a. |only on the outside surface of the sphere. |
|b. |only on the inside surface of the sphere. |
|c. |both on the inside and outside surfaces of the sphere. |
____ 104. The electric field outside a Van de Graaff generator may be enormous, while inside the spherical dome, the electric field is
|a. |even more enormous. |
|b. |almost as enormous. |
|c. |zero. |
____ 105. The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is
|a. |half as much. |
|b. |the same. |
|c. |twice as much. |
|d. |four times as much. |
|e. |none of the above |
____ 106. Two parallel plates are oppositely charged. The left plate is negative and the right plate is positive. In which direction does the electric field point?
|a. |to the left |
|b. |to the right |
____ 107. Electrical potential energy per charge is electric
|a. |force. |
|b. |power. |
|c. |potential. |
|d. |work. |
____ 108. The electric field inside an uncharged metal ball is zero. If the ball gains a negative charge, the electric field inside the ball will be
|a. |greater than zero. |
|b. |less than zero. |
|c. |zero. |
____ 109. If you use 20 J of work to push a 2-C charge into an electric field, its voltage with respect to its starting position is
|a. |10 V. |
|b. |less than 10 V. |
|c. |more then 10 V. |
____ 110. The electrical force on a 2-C charge is 20 N. What is the value of the electric field at the location of the charge?
|a. |2 N/C |
|b. |10 N/C |
|c. |20 N/C |
|d. |40 N/C |
|e. |80 N/C |
____ 111. An electron is pushed into an electric field where it acquires a 7.0-V electric potential. If two electrons are pushed the same distance into the same electric field, the electric potential of the two electrons is
|a. |1.8 V. |
|b. |3.5 V. |
|c. |7.0 V. |
|d. |14.0 V. |
|e. |28.0 V. |
____ 112. In solid conductors, electric current is the flow of
|a. |positive and negative charges. |
|b. |electrons. |
|c. |negative ions. |
|d. |protons. |
|e. |none of the above |
____ 113. Electrons move in an electric circuit
|a. |by being bumped by other electrons. |
|b. |by interacting with an established electric field. |
|c. |by colliding with molecules. |
|d. |because the wires are so thin. |
|e. |none of the above |
| | |
| | |
____ 114. An ampere is a
|a. |unit of resistance. |
|b. |unit of current. |
|c. |type of charge. |
|d. |voltage. |
|e. |current. |
____ 115. Electrical resistance in a wire depends on the wire's
|a. |thickness. |
|b. |conductivity. |
|c. |length. |
|d. |all of the above |
|e. |none of the above |
____ 116. For most conductors, as their temperature increases, their resistance
|a. |decreases. |
|b. |increases. |
|c. |stays the same. |
____ 117. Electrical resistance is measured in
|a. |volts. |
|b. |joules. |
|c. |watts. |
|d. |amperes. |
|e. |none of the above |
____ 118. The voltage of AC current in North America is
|a. |120 V. |
|b. |50 hertz. |
|c. |30 V. |
|d. |60 hertz. |
____ 119. Current from a battery is always
|a. |DC. |
|b. |AC. |
____ 120. Where do the electrons come from that produce heat and light in a light bulb?
|a. |the power company |
|b. |the air |
|c. |the wall plug |
|d. |the bulb's wire filament |
|e. |none of the above |
____ 121. When we say an appliance uses up electricity, we really are saying that
|a. |electrons are taken out of the circuit and put somewhere else. |
|b. |electron kinetic energy is changed into heat and other forms of energy. |
|c. |the main power supply voltage is lowered. |
|d. |current disappears. |
|e. |electric charges are dissipated. |
____ 122. Power outlets in our homes typically have a potential difference of
|a. |30 V. |
|b. |120 A. |
|c. |60 A. |
|d. |240 V. |
|e. |120 V. |
____ 123. When connected to a 110-volt power supply, how much current is in a light bulb that has a resistance of 220 ohms?
|a. |0.5 A |
|b. |2.0 A |
|c. |110 A |
|d. |220 A |
|e. |24,200 A |
____ 124. An electric heater is rated at 300 W for use in a 110-V circuit. The circuit breaker in the circuit can handle 12 A of current. How many heaters can be safely operated in the circuit?
|a. |2 |
|b. |3 |
|c. |4 |
|d. |5 |
|e. |more than 5 |
____ 125. A heater uses 21 A when connected to a 110-V line. If electric power costs 10 cents per kilowatt-hour in this location, the cost of running the heater for 13 hours is _____.
|a. |$0.30 |
|b. |$0.75 |
|c. |$3.00 |
|d. |$7.51 |
|e. |none of the above |
____ 126. A power line with a resistance of 9 ohms has a current of 80 A in it. The power dissipated in the line is
|a. |360 W. |
|b. |720 W. |
|c. |1,440 W. |
|d. |57,600 W. |
|e. |none of the above |
____ 127. In order to form an electric circuit, you need to have
|a. |wires or conductors to connect everything. |
|b. |a power source. |
|c. |a light bulb or some resistance. |
|d. |a complete path for the current. |
|e. |all of the above |
____ 128. In order for current to flow in a circuit, you must have
|a. |a switch that is open. |
|b. |a complete path for the current. |
|c. |two light bulbs in parallel. |
|d. |two light bulbs in series. |
|e. |all of the above |
____ 129. Electrical resistance is measured in
|a. |volts. |
|b. |amperes. |
|c. |joules. |
|d. |watts. |
|e. |none of the above. |
____ 130. A closed circuit is a circuit in which charge
|a. |can flow. |
|b. |is prevented from flowing. |
____ 131. When two light bulbs are connected in series, the
|a. |current through each light bulb is proportional to the resistance of the bulb. |
|b. |same amount of current always flows through each bulb. |
|c. |neither A nor B |
____ 132. The symbol used to represent resistance in a schematic diagram is
|a. |two straight lines. |
|b. |a single line that is broken and has a bend in it. |
|c. |one straight line. |
|d. |a zigzag line. |
|e. |none of the above |
____ 133. When resistors are put in series next to each other, their overall resistance is
|a. |the same as the resistance of one of the resistors. |
|b. |larger than the resistance of any individual resistor. |
|c. |smaller than the resistance of any of the resistors. |
____ 134. When resistors are put in parallel with each other their overall resistance is
|a. |smaller than the resistance of any of the resistors. |
|b. |larger than the resistance of any other resistor. |
|c. |the same as the resistance of one of the resistors. |
____ 135. As more lamps are put into a series circuit, the overall current in the circuit
|a. |stays the same. |
|b. |increases. |
|c. |decreases. |
____ 136. As more lamps are put into a parallel circuit, the overall current in the circuit
|a. |increases. |
|b. |stays the same. |
|c. |decreases. |
____ 137. When one light bulb in a parallel circuit containing several light bulbs burns out, the other light bulbs
|a. |do not burn at all. |
|b. |burn brighter. |
|c. |burn the same as before. |
____ 138. Electrical devices in our homes are connected in
|a. |parallel. |
|b. |series. |
____ 139. Two lamps, one with a thick filament and one with a thin filament, are connected in series. The current is greater in the lamp with the
|a. |thin filament. |
|b. |thick filament. |
|c. |Current is the same in each lamp. |
____ 140. A 60-W light bulb is connected to a 12-V car battery. When another 60-W bulb is connected in parallel with the first bulb, the battery's output energy
|a. |doubles. |
|b. |halves. |
|c. |remains the same. |
____ 141. A 60-W light bulb and a 100-W light bulb are both connected in parallel to a 120-V outlet. Which light bulb has more current in it?
|a. |the 100-W bulb |
|b. |the 60-W bulb |
|c. |Both have the same current. |
____ 142. The current through two identical light bulbs connected in series is 0.25 A. The total voltage across both bulbs is 120 V. The resistance of a single light bulb is
|a. |24 ohms. |
|b. |48 ohms. |
|c. |240 ohms. |
|d. |480 ohms. |
|e. |none of the above |
____ 143. Moving electric charges will interact with
|a. |an electric field. |
|b. |a magnetic field. |
|c. |both A and B |
|d. |none of the above |
____ 144. Surrounding every moving electron is
|a. |an electric field. |
|b. |a magnetic field. |
|c. |both A and B |
|d. |none of the above |
____ 145. If you put a small compass in a magnetic field, the compass will
|a. |line up in a direction parallel to the magnetic field lines. |
|b. |swing randomly. |
|c. |line up in a direction perpendicular to the magnetic field lines. |
|d. |seek electrical charge concentrations. |
____ 146. Magnetic domains are
|a. |regions that may or may not be magnetized. |
|b. |clusters of atoms randomly aligned. |
|c. |regions of atoms magnetically aligned. |
|d. |blocks of material. |
____ 147. The reason a magnet can attract an unmagnetized nail is that
|a. |nails really are magnetized. |
|b. |nails become temporarily magnetized in a magnetic field. |
|c. |nails become permanently magnetized in a magnetic field. |
|d. |a magnet can attract any metal object. |
____ 148. When current passes through a wire, a magnetic field is created around the wire only if the
|a. |wire is absolutely straight. |
|b. |wire is curved in a loop. |
|c. |current makes a complete loop. |
|d. |current comes from a battery. |
|e. |A magnetic field is always created around the wire. |
____ 149. A wire carrying a current is bent into a loop. The magnetic field is strongest
|a. |at the center of the loop. |
|b. |at the edges of the loop. |
|c. |where the loop is located. |
____ 150. Loops of wire in a motor rotate because a
|a. |battery effectively pushes a loop around in the field. |
|b. |current exerts a force on the loop, causing it to rotate. |
|c. |magnetic field exerts forces on moving electrons in the loop. |
|d. |magnet attracts stationary electrons in the wire. |
|e. |none of the above |
____ 151. The magnetic pole in the Northern Hemisphere is located
|a. |in Alaska. |
|b. |in Canada. |
|c. |at the geographic North Pole. |
|d. |just north of the United States. |
|e. |none of the above |
____ 152. Changing the magnetic field intensity in a closed loop of wires induces
|a. |current. |
|b. |voltage. |
|c. |both current and voltage. |
|d. |neither current nor voltage. |
____ 153. A magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the induced voltage
|a. |is the same. |
|b. |doubles. |
|c. |quadruples. |
|d. |halves. |
|e. |none of the above |
____ 154. A device consisting of a coil that is mechanically rotated in a stationary magnetic field is called
|a. |a motor. |
|b. |a magnetic pole. |
|c. |a generator. |
|d. |a transformer. |
|e. |a dipole. |
____ 155. A generator is used to light a bulb. Energy for lighting the bulb actually comes from
|a. |a plug where the generator is connected to the wall. |
|b. |a mechanical input to the generator. |
|c. |the magnet in the generator. |
|d. |the coil of wire. |
|e. |none of the above |
____ 156. If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with a greater speed
|a. |a larger voltage is induced. |
|b. |a smaller voltage is induced. |
|c. |the same voltage is induced. |
____ 157. In an electromagnetic wave, the electric and magnetic fields are _____ to each other and _____ to the direction of wave motion.
|a. |opposite, parallel |
|b. |at right angles, perpendicular |
|c. |parallel, at right angles |
|d. |at right angles, parallel |
____ 158. A transformer works because
|a. |electricity flows from a primary coil to a secondary coil. |
|b. |electricity is induced in a rotating coil. |
|c. |a changing magnetic field is transferred to a coil via an iron core. |
|d. |electricity is transferred to a coil via an iron core. |
| | |
____ 159. A transformer transforms
|a. |magnetic field lines. |
|b. |generators into motors. |
|c. |voltage. |
|d. |unsafe forms of energy into safe forms. |
____ 160. A step-up transformer
|a. |doesn't change the voltage at all. |
|b. |decreases voltage. |
|c. |increases voltage. |
____ 161. The principal advantage of AC power over DC power is that
|a. |AC voltage oscillates, whereas DC voltage does not. |
|b. |lower voltages are used. |
|c. |AC circuits multiply power more easily. |
|d. |AC voltage can be transformed more easily. |
|e. |AC circuits are safer. |
____ 162. If a transformer increases AC voltage, it will also increase
|a. |energy. |
|b. |magnetic field strength. |
|c. |power. |
|d. |current. |
|e. |none of the above |
____ 163. Light behaves as a
|a. |wave. |
|b. |particle. |
|c. |both A and B |
|d. |none of the above |
____ 164. The energy of a photon is directly proportional to its
|a. |speed. |
|b. |amplitude. |
|c. |period. |
|d. |frequency. |
|e. |wavelength. |
____ 165. Which of the following radiation have the greatest energy?
|a. |blue light |
|b. |yellow light |
|c. |green light |
|d. |red light |
|e. |ultraviolet |
____ 166. The ratio of a photon's energy to its frequency is
|a. |its wavelength. |
|b. |its speed. |
|c. |Planck's constant. |
|d. |its amplitude. |
|e. |none of the above |
____ 167. Which experiences the greatest electrical force in an electric field?
|a. |an alpha particle |
|b. |a gamma ray |
|c. |a beta particle |
|d. |a proton |
|e. |same force for all of the above |
Free Response Problems
168. 100,000 electrons are removed from a neutral plastic ball. What is its charge?
169. What is the magnitude of the force on an electron in an electric field of 400 N/C?
170. How much voltage is required to make 4 amperes flow through a 12-ohm resistor?
171. A battery does 18 J of work on 10 coulombs of charge. What voltage does the battery supply?
172. What is the power dissipated by a toaster that has a resistance of 40 ohms and is plugged into a 120-V outlet?
173. A certain bulb with a resistance of 240 ohms is labeled 60 W. For what voltage circuit was this bulb designed?
174. Two identical resistors in parallel have an equivalent resistance of 7 ohms. If the same resistors were instead connected in series, what would be the equivalent resistance?
175. A 30-V potential difference is applied across a series combination of an 8.0-ohm resistor and a 3.0-ohm resistor. What is the current in the 8.0-ohm resistor?
176. A 60-V potential difference is applied across a parallel combination of a 10-ohm and a 20-ohm resistor. What is the current in the 10-ohm resistor?
177. A 20.0-V potential difference is applied across a parallel combination of a 60.0-ohm and a 10.0-ohm resistor. What is the current in the 10.0-ohm resistor?
178. A step-up transformer has 40 turns on its primary and 100 turns on its secondary. When the primary is supplied with an alternating current at 140 V, what is the voltage across the secondary?
179. A step-up transformer has 250 turns on its primary and 500 turns on its secondary. When the primary is connected to 120 V and the secondary is c
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