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Definitions |
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Electroplating uses ___ electricity
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DC
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X-rays were discovered by
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Wilhelm Roentgen
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Using a pre-charged electroscope, when a charged test object is brought near the ball, the leaves move closer together. This indicates that the test object charge is the _____ polarity as the electroscope charge
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Opposite
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An electrical connection made by connecting to a rod or pipe physically driven into the ground is called a ____ground
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Earth
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Testing conductor insulation should be done using voltages that are near the operating voltage of the conductor. This cannot be done with most ohmmeters because the ohmmeter supply is often a battery and the voltage used is often less than a few volts. Th
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MEGGER
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The process of separating elements electrically is known as
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electrolysis
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A lightning arrester is used for lightning protection, but is not designed to be struck by lightning itself (lightning rods do). If the protected object is struck by lightning, the high voltage of the lightning _____ across to the lightning arrestor and b
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arcs
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The strength of an electromagnet is primarily proportional to its
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Ampere-turns
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An electrical device is listed as 3,000 watts. Approximately how many horsepower is this?
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4
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A magnet that produces a magnetic field as the result of current flow in a conductor is called a(n)
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Electromagnet
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The measure of a material's resistance to being magnetized is called
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Reluctance
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In a parallel circuit, several resistors are connected to a single power source. Each separate resistor circuit is called a
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Circuit branch
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A digital ohmmeter CANNOT be connected to a circuit when the power is turned ON
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...
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If a particular hook-up requires very large conductors, it may be better to use several smaller conductors to carry the current. When this arises, the several smaller conductors are connected to each other in
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parallel
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Secondary cell
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a cell which can be recharged
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The operating principles of the cathode-ray tube were discovered by
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J.J. Thomson
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The nucleus of an atom contains
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Neutrons and protons
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The measure of a material's ability to become magnetized is called
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Permeability
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If a series circuit has resistor values of 27 ohms, 56 ohms, and 82 ohms, the total resistance is
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165 ohms
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The polarity of the voltage across a resistor depends on the direction of current flow through the resistor. The end of the resistor into which current enters is assigned the polarity of
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negative
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In a parallel circuit, an increase in current flow in a branch results in an increase of the ____ of the branch
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Load
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A three branch parallel circuit has resistors of 27 ohms, 56 ohms, and 15 ohms. What is the total resistance?
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8.23 ohms
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The most common type of ohmmeter is the series type. On an analog series ohmmeter scale, zero is on the
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right
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It is common for voltmeters to be multirange
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...
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A ____ circuit is a common circuit configuration used in measuring resistance, inductance, and capacitance
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bridge
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If two conductors are not touching but are close to each other, a large enough voltage will cause an ____ to occur between the conductors
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arc
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The process of depositing one type of metal onto another using electricity is called
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electroplating
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Write the equation for the R-L time constant that will compute one time constant
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T=L/R
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Static electricity is a ____, not a _____
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Charge; current
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A variable resistor with two terminals is called a
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Wire wound resistor
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In a circuit, when the two conductors leading from and back to the power source become connected, this establishes a separate current path that bypasses the load. This is called what?
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Short circuit
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During the solving of a combination circuit, it is necessary to simplify a parallel block to
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One series resistor
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A series circuit is a circuit that has only one path for ____flow
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Current
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The low impedance voltage tester is most suitable for use in
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high power circuits
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A voltaic cell can be constructed of two ____ metals and an ____
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unlike; electrolyte
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X-rays are an example of the result of conduction in a
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gas
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What charge does an ion have
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either positive or negative
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A conductor is normally made of atoms with how many electrons in the valence shell
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One to three
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Connecting a 150 ohm, ½-W resistor to a 9v power supply will ____
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Damage the resistor
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A simple parallel circuit is a circuit that contains
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Only parallel elements
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A wire that has a diameter of 162 mils has an area of ___ circular mils
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26,244
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If a DC voltage is connected to an inductor, during the period of time called the first time constant, the current will rise to about ___ % of its full value
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63.2 %
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The low of charges states that:
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Like charges repel and opposite charges attract
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A device that can be used for spike suppression in either DC or AC circuits is the
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metal oxide varistor
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In a circuit, three wires form a junction. The currents in two of the wires are 5 A and 12 A. The current in the other wire is
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7 A or 17 A
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When considering conduction in a gas, the speed an electron obtains is
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Proportional to the applied voltage and the distance travelled before striking a gas molecule
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Three factors determine the amount of voltage induced into a conductor moving in a magnetic field:
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cutting action speed; number of wire turns; strength of magnetic field
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A henry (H) is defined as...
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when a CURRENT CHANGE of 1 ampere per second results in an induced voltage of 1 VOLT
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Once an arc is established across an air gap in an electrical circuit surrounded by a gas, the voltage required to maintain conduction is
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less than that required to start the arc
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There are two conductors, a red and a blue installed in metallic conduit. You are using a MEGGER to test for GROUNDS. The two leads of the MEGGER should be connected
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one to the red lead and one to the conduit; one to the blue lead and one to the conduit
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