Objective #15
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DC motors are fairly simple and inexpensive to make. True False
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True
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The field(s) surrounding every moving neutron is(are) always magnetic but never electric. always electric but never magnetic. sometimes magnetic and sometimes electric. always both electric and magnetic. none of the above
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none of the above
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If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil at half the speed, one half as much voltage is induced. the same voltage is induced. twice as much voltage is induced. four times as much voltage is induced. none of these
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one half as much voltage is induced.
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The reason a magnet can pick up an unmagnetized steel paper clip is that paper clips are actually magnetic. the magnet temporarily magnetizes the paper clip. electrons in the paper clip are attracted to the magnet. protons in the paper clip are attracted to the magnet.
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the magnet temporarily magnetizes the paper clip.
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If the north pole of a magnet is thrust into a closed loop of wire and produces a positive current, then when it is pulled back out of the loop the current will be also positive. negative. no current produced when it leaves the loop.
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negative.
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A device that transforms mechanical energy into electrical energy is a generator. motor. transformer. magnet. none of these
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generator.
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A device that transforms electrical energy to mechanical energy is a generator. motor. transformer. magnet. none of these
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motor.
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Which scientist discovered the process known as electromagnetic induction? Michael Faraday Ben Franklin Thomas Edison Hans Christian Oersted Allesandro Volta Andre Marie Ampere
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Michael Faraday
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An electromagnet is made by wrapping insulated wire around a steel nail and connecting the wire ends to a dry cell battery. If you want this electromagnet to reverse its north and south poles, then you should reverse the current flow. wrap the nail the opposite way. reverse the current flow AND wrap the nail the opposite way. reverse the current flow OR wrap the nail the opposite way, but not do both. point the nail in the opposite direction.
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reverse the current flow OR wrap the nail the opposite way, but not do both.
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Oil and coal power plants produce electricity because burning the oil and coal produces electrically charged particles. current in a wire. chemical changes that produce current. tremendous amounts of heat. radioactive waste.
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tremendous amounts of heat.
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The reason a magnet will not pick up an unmagnetized plastic paper clip is that plastic paper clips are actually diamagnetic. electrons in the plastic paper clip are repelled by the magnet. protons in the paper clip are repelled the magnet. the magnet cannot temporarily magnetize the plastic paper clip.
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the magnet cannot temporarily magnetize the plastic paper clip.
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An electric motor is very similar to an electric generator. an automobile battery. a radio receiver. None of the above choices are correct.
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an electric generator.
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Magnetic field lines about a current-carrying wire extend radially from the wire. circle the wire in closed loops. Choices A and B are both correct. None of the above choices are correct.
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circle the wire in closed loops.
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The south pole of a bar magnet is used to pick up a steel paper clip. Turn the magnet around and the bar magnet's north pole will still pick up the paper clip. now repel the paper clip. have no effect on the paper clip.
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still pick up the paper clip.
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Like kinds of magnetic poles repel while unlike kinds of magnetic poles attract. repel also. may attract or repel.
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attract.
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An electromagnet is made by wrapping insulated wire around a steel nail and connecting the wire ends to a dry cell battery. If you want this electromagnet to reverse its north and south poles, then you should reverse the current flow. wrap the nail the opposite way. reverse the current flow AND wrap the nail the opposite way. reverse the current flow OR wrap the nail the opposite way, but not do both. point the nail in the opposite direction.
answer
reverse the current flow OR wrap the nail the opposite way, but not do both.
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Break a magnet in two and you produce two magnets, each with north and south poles, only if the original magnet was large enough. end up with two pieces, one piece is a north pole and the other piece is a south pole, if the magnet was small enough. always end up with two pieces, one piece is a north pole and the other piece is a south pole, no matter how big the original magnet was. always produce two magnets, each with north and south poles, no matter what the size of the original magnet.
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always produce two magnets, each with north and south poles, no matter what the size of the original magnet.
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Which scientist discovered that a compass needle may be is deflected by a current-bearing wire? Michael Faraday Ben Franklin Thomas Edison Hans Christian Oersted Allesandro Volta Andre Marie Ampere
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Hans Christian Oersted
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A device that transforms mechanical energy into electrical energy is a generator. motor. transformer. magnet. none of these
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generator.
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Which scientist is credited for inventing the first electric motor? Michael Faraday Ben Franklin Thomas Edison Hans Christian Oersted Allesandro Volta Andre Marie Ampere
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Michael Faraday
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Which of the following materials contain billions of electrons in motion that are surrounded by tiny magnetic fields? copper wire iron nail plastic paper clip wood ruler only a and b only c and d all four of these
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all four of these
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The south pole of a bar magnet is used to pick up a steel paper clip. Turn the paper clip around and the bar magnet's south pole will still pick up the paper clip. now repel the paper clip. have no effect on the paper clip.
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still pick up the paper clip.
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A device that transforms electrical energy to mechanical energy is a generator. motor. transformer. magnet. none of these
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motor.
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An electric motor is very similar to an electric generator. an automobile battery. a radio receiver. None of the above choices are correct.
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an electric generator.
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Electromagnets may be made stronger by wrapping them with more turns of wire. increasing the current flow around them. wrapping the wire around better conducting copper wire. all of these only a and b
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only a and b
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The reason a magnet will not pick up an unmagnetized plastic paper clip is that plastic paper clips are actually diamagnetic. electrons in the plastic paper clip are repelled by the magnet. protons in the paper clip are repelled the magnet. the magnet cannot temporarily magnetize the plastic paper clip.
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the magnet cannot temporarily magnetize the plastic paper clip.
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When the world one day runs out of oil, we will not be able to produce electricty anymore. True False.
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False.
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Magnetism is due to the motion of electrons as they move around the nucleus. spin on their axes. Choices a and b are both correct. None of the above choices are correct.
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Choices a and b are both correct.
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Nuclear power plants produce electricity because the nuclear reactions produce electrically charged particles. tremendous amounts of heat. current in a wire. chemical changes that produce current. radioactive waste.
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tremendous amounts of heat.
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The reason a magnet can pick up an unmagnetized steel paper clip is that paper clips are actually magnetic. the magnet temporarily magnetizes the paper clip. electrons in the paper clip are attracted to the magnet. protons in the paper clip are attracted to the magnet.
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the magnet temporarily magnetizes the paper clip.
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When a magnet moves in and out of a closed loop of wire, the type of electricity that is generated is known as alternating current. direct current. ac/dc current. bipolar current. reciprocal current.
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alternating current.
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Several paper clips dangle in a chain from the north pole of a magnet. The induced pole in the bottom of the lowermost paper clip is a Selected Answer: north pole. Answers: north pole. south pole. north or south pole - no difference really.
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north pole.
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Oil and coal power plants produce electricity because burning the oil and coal produces electrically charged particles. current in a wire. chemical changes that produce current. tremendous amounts of heat. radioactive waste.
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tremendous amounts of heat.
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If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with twice the number of loops, one half as much voltage is induced. the same voltage is induced. twice as much voltage is induced. four times as much voltage is induced. none of these
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twice as much voltage is induced.
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Break a magnet in two and you produce two magnets, each with north and south poles, only if the original magnet was large enough. end up with two pieces, one piece is a north pole and the other piece is a south pole, if the magnet was small enough. always end up with two pieces, one piece is a north pole and the other piece is a south pole, no matter how big the original magnet was. always produce two magnets, each with north and south poles, no matter what the size of the original magnet.
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always produce two magnets, each with north and south poles, no matter what the size of the original magnet.
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If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil at twice the speed, one half as much voltage is induced. the same voltage is induced. twice as much voltage is induced. four times as much voltage is induced. none of these
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twice as much voltage is induced.
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Like kinds of magnetic poles repel while unlike kinds of magnetic poles attract. repel also. may attract or repel.
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attract.
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When a magnet is plunged in and out of a closed coil of wire, voltage is induced in the coil. If the rate of the in-and-out motion is tripled, the induced voltage is cut in half. divided by three. doubled. tripled. unchanged.
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tripled.
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Magnetic field lines about a current-carrying wire extend radially from the wire. circle the wire in closed loops. Choices A and B are both correct. None of the above choices are correct.
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circle the wire in closed loops.
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The reason a magnet will not pick up an unmagnetized plastic paper clip is that plastic paper clips are actually diamagnetic. electrons in the plastic paper clip are repelled by the magnet. protons in the paper clip are repelled the magnet. the magnet cannot temporarily magnetize the plastic paper clip.
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the magnet cannot temporarily magnetize the plastic paper clip.
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The field(s) surrounding every stationary neutron is(are) always magnetic but never electric. always electric but never magnetic. sometimes magnetic and sometimes electric. always both electric and magnetic. none of the above
answer
none of the above
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If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil at half the speed, one half as much voltage is induced. the same voltage is induced. twice as much voltage is induced. four times as much voltage is induced. none of these
answer
one half as much voltage is induced.
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Electromagnets can be made weaker by wrapping them with more turns of wire. wrapping them with fewer turns of wire. increasing the current through the wire. decreasing the current through the wire both a and c. both b and d.
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both b and d.
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If the north pole of a magnet is thrust into a closed loop of wire and produces a positive current, then when it is pulled back out of the loop the current will be also positive. negative. no current produced when it leaves the loop.
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negative.
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Magnetism is due to the motion of electrons as they move around the nucleus. spin on their axes. Choices a and b are both correct. None of the above choices are correct.
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Choices a and b are both correct.
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The picture above shows how to make an electromagnet. how to generate alternating current electricity. how to detect the magnetic field around a current-bearing wire. how to make a simple electric motor.
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how to make an electromagnet.
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The field(s) surrounding every moving electron is(are) always magnetic but never electric. always electric but never magnetic. sometimes magnetic and sometimes electric. always both electric and magnetic. none of the above
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always both electric and magnetic.
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Several paper clips dangle in a chain from the south pole of a magnet. The induced pole in the bottom of the lowermost paper clip is a north pole. south pole. north or south pole - no difference really.
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south pole.
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The field(s) surrounding every moving neutron is(are) always magnetic but never electric. always electric but never magnetic. sometimes magnetic and sometimes electric. always both electric and magnetic. none of the above
answer
none of the above
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The field(s) surrounding every stationary electron is(are) always magnetic but never electric. always electric but never magnetic. sometimes magnetic and sometimes electric. always both electric and magnetic. none of the above
answer
always electric but never magnetic.
