MindTap AC/DC Practice Test

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• Which expression correctly represents the impedance of an inductor in phasor form?
• What is Thevenin's Theorem and what problem does it solve?
• A basic law of magnetism states that unlike poles repel and like poles attract.
• The charge accumulates on an object is determined by the ___ used to produce the charge.
• The statement 'The most common method of producing electricity is magnetism' is
• Describe the RL-transient response of current when a step voltage is applied.
• The voltage across a resistor is proportional to its what?
• If one branch draws more current, the total current in the circuit will increase.
• Which statement correctly describes how X_L and X_C change as angular frequency ω increases?
• What is Norton’s Theorem and how does it relate to Thevenin’s?
• The values of a variable resistor can be changed or varied over a range.
• If a raceway contains no more than 3 conductors, the ampacity must be ___.
• The longer the conductor, the less the resistance it will have.
• Which statement about static electricity and thunderstorms is true?
• Valence electrons are located in the outer shell of an atom.
• In a parallel circuit, the current through a branch is inversely proportional to the branch's resistance.
• A voltage multiplier is used to provide different voltages between certain points in a circuit.
• A ____ is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
• Which law is not used to relate current, voltage, power, and resistance in a series circuit?
• Which statement about insulators is true?
• In phasor form, what is the impedance of a capacitor?
• The function of a wattmeter is to measure what quantity?
• In an ideal transformer, which relationships hold between primary and secondary voltages, currents, and turns?
• The junction point at which currents split is called what in circuit terminology?
• In a series RLC circuit, when X_L equals X_C, the impedance is purely real and equals which value?
• A voltage multiplier is used to provide different voltages between points in a circuit.
• Which statement correctly describes the Norton equivalent?
• Which statement about parallel circuits is true?
• Resistance is measured with a voltmeter.
• Nuisance static charges are more likely to occur when the air is wet.
• Which factor primarily influences the strength of an electromagnet?
• After obtaining Thevenin equivalent, how is the load voltage determined with R_th and V_th present?
• For two impedances Z1 and Z2, what are the series and parallel formulas for total impedance?
• Which expression gives the Q factor for a series RLC circuit in terms of L, C, and R (without using ω0)?
• In a parallel circuit, the total resistance is less than that of the lowest value resistor.
• Which statement correctly describes the interaction of magnetic poles?
• Materials that _____ their resistance with an increase in temperature have a positive coefficient of temperature.
• Which factor is used to determine conductor ampacity in relation to temperature?
• In the NEC, ampacities refer to the ____ abilities of conductors.
• Which diameter in mils yields an area of 26,244 circular mils?
• How do X_L and X_C vary with frequency, and what is the behavior of a series LC circuit as frequency changes?
• What is the impedance of a resistor in phasor form?
• Which type of resistor offers a higher power rating?
• If the power between two points of a conductor is one watt and the current is one amp, the potential difference between those points is what?
• Di­amagnetic materials are either metal or nonmetal materials that cannot be magnetized.
• In AC circuits, how are frequency, angular frequency, and period related?
• Ampacity relates to the conductor's ability to carry current.
• The ohmmeter must be connected to a circuit when the circuit power is turned on.
• When the current in a combination circuit reaches a node, the current is blocked.
• The static charge that accumulates on clothes in a dryer is a useful charge.
• In a parallel circuit, the voltage across each branch is equal to the applied voltage.
• A multirange ammeter operates on more than one range by connecting the meter movement to different shunts.
• Ferromagnetic materials are metals that are easily magnetized.
• Voltage drop across a resistor in a circuit can be calculated using Ohm's law.
• Which equation expresses the reciprocal of the total impedance for two parallel impedances as the sum of reciprocals?
• The most common method of producing electricity is magnetism.
• In a series RLC circuit at frequency ω, which expression correctly gives the current I in terms of V and the impedance Z = R + j(ωL − 1/(ωC))?
• The smallest part of a compound is the ____.
• If φ = atan(X/R) for a series circuit, the power factor PF = cos φ. If X > 0, the power factor indicates which of the following?
• Wattage is also referred to as emf.
• The discharge of ____ in thunderclouds creates lightning bolts.
• One method for finding the total resistance of parallel resistors is to multiply the resistances and divide by their sum.
• A wire-wound resistor is made by winding a piece of resistive wire around a ceramic core.
• What is the cutoff frequency for a first-order RC low-pass filter?
• What is Ohm's Law and how does it apply to a DC resistor?
• Which factor does not determine the strength of an electromagnet?
• Define the RC time constant and explain its role in charging a capacitor through a resistor.
• Insulators are the only materials that can hold electrons stationary.
• Permeability is the measure of a material's ability to be magnetized. Which term is defined by this measure?
• Which device is connected directly across the power source due to its high resistance in series with the meter movement?
• Direct current is described as bidirectional.
• The unit of resistance to current flow is the ohm.
• Which band of color on a resistor indicates tolerance?
• A neutral conductor is also referred to as a ground conductor.
• To identify series and parallel elements in a combination circuit, you should trace the currents path(s).
• A complete circuit is often referred to as an open circuit.
• Which instrument is designed to minimize circuit disturbance when measuring current?
• Which of the following is the smallest part of an element?
• Which class of materials exhibits spontaneous alignment of magnetic moments in the absence of an external magnetic field?
• What device is a variable resistor used to provide a variable voltage?
• Rc(2&3) refers to the _____ containing R2 and R3.
• A wire-wound resistor is made by winding a piece of resistive wire around a ceramic core.
• What is the effect of adding a capacitor in parallel with a resistor on the combined impedance and phase at a given frequency?
• When conductors are used in a location with a higher ambient temp, the amp of the conductor must be reduced.
• Which statement correctly describes the ohm?
• An increase of current, not resistance, results in an increase of load.
• When determining the total resistance in a parallel circuit, the reciprocal of any number is that number divided by 1.
• What is the capacitor voltage during charging in an RC circuit after a step input?
• In a parallel resonant circuit, how does the Q-factor influence the bandwidth around resonance?
• What is the sign of the imaginary part of the capacitor impedance Z_C = 1/(j ω C)?
• In solving combination circuits, tracing currents to identify series and parallel elements is ____.
• The statement 'A short circuit occurs when there is very little resistance and a large amount of current flow' is:
• For a sinusoidal signal, what is the relation between V_peak and V_rms?
• Power lines are typically protected by lightning arrestors that exhibit a very high resistance at normal voltages.
• An ammeter shunt is a high-resistance device.
• In a series circuit, the total resistance to current flow is equal to the sum of the resistances. This summation is with respect to what parameter?
• The ampere is equal to one coulomb per second.
• In a parallel circuit, the total current flow equals the sum of the currents through all branches.
• The cross-sectional area of round wire is measured in circular mils.
• A circuit that contains both series and parallel elements is called a ____ circuit.
• How do you determine the Thevenin equivalent of a circuit seen by a load?
• The term ampacity describes the conductor's ability to carry current.
• What term describes a circuit that contains both series and parallel elements?
• Static electricity is caused by a balance of electrical charges.
• The voltage drop across any branch of a parallel circuit is the same as the applied voltage.
• Which statement is true according to the provided information?
• When calculating R_th by deactivating independent sources, which actions are performed?
• A rheostat is a common name for which type of resistor?
• If the frequency doubles, what happens to the capacitive reactance X_C = 1/(ω C)?
• Lightning bolts are created by the discharge of static electricity in thunderclouds.
• In a series circuit, how many paths are there for current flow?
• Which instrument is designed to be connected in parallel with the element under test?
• For a series RC low-pass filter with transfer function H(jω) = 1 / (1 + j ω R C), what is the magnitude |H(jω)|?
• What is the relationship between the RMS value and the peak value of a sine wave?
• ___ are used to detect spike voltages, or currents of short duration, or sudden drops in voltage, current, or power.
• What is the energy stored in an inductor when the current through it is I?
• What is a phasor in AC circuit analysis?
• Which resistor type is commonly used when high power rating is necessary due to its construction?
• What practical method is used to improve power factor in an inductive circuit?
• A method for finding total resistance of parallel resistors is calculating the product over the sum.
• Which expression correctly represents the power dissipated by a resistor given current I and resistance R?
• What type of variable resistor is typically used to provide a variable voltage?
• In a circuit with two series impedances Z1 and Z2, what is the expression for the voltage across Z1 (V1)?
• In a series RC circuit, express the steady-state current as a function of V, R, C, and frequency.
• Which particle can form spin patterns that cancel the magnetic field of a material?
• The instantaneous power p(t) in an AC circuit is given by which expression?
• Amperes are defined as coulombs per second.
• _____ is defined as the potential difference between two points of a conducting wire carrying a constant current of one amp when the power dissipated between these points is one watt.
• A chassis ground symbol symbolizes a ground point.
• How do series and parallel resistor networks differ in their equivalent resistance?
• The meter that measures true power in a circuit is the wattmeter.
• Given a complex impedance Z = R + jX, which statement correctly identifies its complex conjugate and how to compute the power factor from Z?
• In a series circuit, the _____ is equal to the sum of the voltage drops across all the resistors.
• In a series circuit containing a resistor and inductor, what is the phase relationship between current and voltage?
• Which meter is commonly used to measure low resistance with a shunt?
• In electrical schematics, symbols are used to represent which property of a resistor?
• Which term describes the rate of energy transfer or power in an electrical circuit?
• Which statement best describes impedance matching in AC signal transmission?
• The NEC 310 contains tables dealing with what for general wiring?
• As frequency increases, the phase of the impedance of a parallel RC circuit approaches which value?
• The general divider formula can be used to determine voltage drop across series elements.
• A fuse opens a circuit in the event of excessive what?
• Which theory states that current flows from the most positive point to the most negative point in a circuit?
• In a parallel circuit, the amount of current that flows through each resistor is inversely proportional to the resistance value.
• The voltage across a resistor is proportional to which property?
• In a series circuit, the total resistance is equal to the sum of the individual resistances with respect to current flow.
• A 120 V RMS source feeds a series RLC circuit with R = 40 Ω, L = 0.2 H, C = 0.001 F at f = 60 Hz. The power factor is approximately
• Which formula is used to determine the voltage drop across series elements?
• Which quantity's direction helps determine voltage polarity?
• What unit is used to express the cross-sectional area of a round wire?
• The ____ theory states that current flow is produced when an electron from one atom knocks electrons of another atom out of orbit.
• For Z = R + jX, what is the magnitude |Z|?
• A chassis ground is a point that is used as a common connection for other parts of a circuit.
• What is the energy stored in a capacitor when voltage V is across it and the capacitance is C?
• What is the magnitude of the impedance Z for a series RC circuit?
• In resistor color coding, which band indicates tolerance?
• Provide a method to compute the resultant phasor from two sinusoidal voltages with same frequency but different amplitudes and phase angles.
• The nonconductive covering around a wire is the conductor.
• Solving combination circuits includes a step in which you expand the circuit.
• What is the name for a naturally occurring magnetic material previously known as magnetite?
• A series circuit has more than one path to current flow.
• Which statement best describes the relationship between Thevenin and Norton equivalents?
• Producing electricity from light involves the use of particles called ____.
• Diamagnetic materials are repelled by magnetic fields.
• What is the impedance of two impedances in series?
• Valence electrons are located in the outer shell of an atom.
• The smallest part of an element is an atom.
• The strength of an electromagnet is primarily proportional to its diameter.
• The d'Arsonval movement is one of the most common ______ meter movements.
• Voltage polarity can be determined by observing the direction of what?
• Critical damping occurs in a series RLC circuit when the resistance R satisfies which condition in terms of L and C?
• A material with a positive coefficient of temperature has resistance that increases with temperature.
• In a sinusoidal signal, the peak-to-peak voltage is related to the peak voltage by which relation?
• The statement 'The atomic number of an element is the same as the number of electrons in the nucleus' is
• The junction point where a current splits in a circuit is commonly called a ___.
• A metal glaze resistor is made by applying a film of metal to a ceramic rod in a vacuum.
• Selenium is an insulator.
• An ammeter has a typical impedance of less than ____ ohm(s).
• Which statement best describes static electricity as presented?
• Most devices such as light receptacles in homes are connected in series.
• Producing electricity by ____ is an example of static charge.
• The production of electricity by ____ involves the striking, bending, or twisting of certain crystals.
• The current divider formula can be used to calculate current flow through any branch of a circuit.
• The measure of a material's resistance to magnetism is known as reluctance.
• Which expression represents the reactive power Q in an AC circuit with RMS voltage V_rms, RMS current I_rms, and phase angle φ between voltage and current?
• Which statement describes how the Thevenin voltage V_th is determined for a circuit seen at its terminals?
• Emf is synonymous with wattage according to the material.
• Magnetism can be explained in terms of which of the following?
• In a parallel circuit, the total current equals the sum of the currents through all branches.
• Resistors with several non-adjustable ohmic values are called fixed resistors.
• In a series RC low-pass filter, at low frequencies the output is approximately:
• In electrical schematics, symbols are used to represent the resistance of a resistor.
• Power lines are often protected by lightning _____ that exhibit a very high resistance at the normal volt of the line.
• Which magnetic pole of a compass needle is attracted to the south magnetic pole of the Earth?
• The ___ conductor is used to help prevent a shocking hazard in the event that the hot conductor comes in contact with the case or frame of the appliance.
• Which theory states that current flows from the most negative point in a circuit to the most positive point?
• What is the resonance condition for a series RLC circuit and the impedance at resonance?
• Voltage drop can be calculated using Ohm's law.
• What type of ohmmeter is used to measure low values of resistance?
• In a parallel circuit, the total resistance is always less than the smallest individual resistor.
• A ____ can be connected directly across the power source because it has a very high resistance connected in series with the meter movement.
• The atomic number of an element is the same as the number of electrons in the nucleus.
• What is the cutoff frequency for a first-order RC high-pass filter?
• An early electric instrument that can be used to determine the polarity of the electrostatic charge of an object is the ____.
• The current through a load connected to a Thevenin equivalent with complex impedance Z_th and Z_load is given by which expression?
• What is a natural display of static electric discharge?
• The ambient air temperature considered in relation to a conductor ampacity is the temperature of the surrounding air.
• In a parallel LC circuit at resonance, what happens to the impedance and the source current?