DC Theory LMS Practice Test

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• Electromotive force is measured in which unit?
• What is the current through the 8 Ω resistor in the 30 V parallel circuit?
• In a conductor, increasing the length will cause resistance to
• Which theorem states that any linear source can be replaced by an equivalent current source in parallel with a resistor?
• In series circuits, which quantity remains the same through all components?
• In an industrial setting, damages from using a residential meter could include?
• Adding parallel loads to a circuit will cause total circuit resistance to ... and total circuit current to ...
• Identify the type of circuit that would have no current flow through it.
• In the Left-Hand Rule for generators, which trio is described for electromagnetic induction?
• Which is the Norton equivalent of a 10 V source in series with a 5 Ω resistor?
• When working your way back up through your redraws, the ... can be determined using Ohm's Law because the ... for that group of components is the same when they are in series.
• The attraction or repulsion that occurs when magnets are held close to each other is caused by ?
• Determine the total resistance in a circuit where the power dissipated is 25 watts and the supplied voltage is 50 volts.
• Transform a 10 V voltage source in series with a 5 Ω resistor to its Norton equivalent.
• Circular mils are the units used to measure the ?
• When it becomes difficult to recognize which components of a circuit are in series and which are in parallel, it can be helpful to ... the circuit.
• Which particle carries a negative charge in an atom?
• Which statement is true about magnetic poles?
• Define short-circuit current and explain its relation to Thevenin equivalents.
• The number of actions that allow a switch to be closed is referred to as the ? of the switch.
• Provide the formulas for converting a delta network Rab, Rbc, Rca to a Y network Ra, Rb, Rc.
• The value 200,000 ohms can also be expressed as ?.
• Using Ohm's Law, the voltage across a component is V = I × R; if I = 2 A and R = 3 Ω, V equals?
• In a circuit containing dependent sources, maximum power transfer occurs when the load resistance equals what?
• The current that leaves and re-enters a single power source in a parallel circuit is called the total current.
• What does the formula R = K x L/ A calculate?
• Increasing the number of loops in a coil will increase the ? of the magnetic field.
• In a Thevenin equivalent with a load R_L in series, which expressions correctly give the current and the load voltage?
• Which of the following pairs are the two general types of resistors?
• Which equation expresses Ohm's Law for a resistor?
• The unit that represents the amount of resistance required to allow one amp through when one volt is applied is called a(n) ?.
• Normal switch ratings on a switch include the values of the maximum current and the maximum what?
• In a series circuit with 6 Ω and 3 Ω resistors connected to a 9 V source, what is the current and the voltage drop across each resistor?
• The Left-Hand Rule is used to determine the direction of current in which phenomenon?
• For a load connected to a Thevenin source, which statement is correct about maximum power transfer?
• In a series circuit, the total power is equal to the sum of the power dissipated by each resistor.
• In AC generators, slip rings serve to transfer current without reversing polarity.
• In steady-state DC analysis, what is the typical behavior of an inductor and of a capacitor?
• Which formula expresses power as P = I^2 × R?
• Which option correctly describes the magnetic field lines around a straight current-carrying conductor?
• What shape do the magnetic field lines form around a straight current-carrying conductor?
• Like poles of a magnet ? and unlike poles ? .
• Which statement best describes current distribution in a parallel circuit?
• In the hydraulic-electrical analogy, which electrical quantity corresponds to the flow rate of water in a pipe?
• Using P = I^2 × R, what is the power for a circuit with I = 3 A and R = 4 Ω?
• In a series circuit, there is only one path for current to flow.
• What is the formula for finding total current in a parallel circuit when component currents are known?
• What is the issue with connecting two ideal voltage sources of different voltages in parallel, and how should it be resolved in circuit analysis?
• Electromotive force is another term commonly used for which quantity?
• In a parallel circuit, the voltage across each branch is equal to the total voltage.
• In a parallel circuit, the voltage across each branch is the same.
• The flux lines around a magnet leave the north pole and enter the south pole. Which statement correctly describes the direction of the flux lines?
• One way to calculate the total power in a series circuit is to ? the component wattages.
• Which factors influence the resistance of a wire, according to the formula R = K x L / A?
• In a series circuit, how is total resistance calculated?
• What happens when unlike poles are brought together?
• The ... can be determined using Ohm's Law and the ... any time there are components in series with the source.
• In a circuit with a parallel combination of 8 Ω and 12 Ω across a 30 V source, what is the total current from the source?
• The ohm is the unit of electrical resistance.
• When controlling a load from three locations, a ? is used in conjunction with two ?.
• Ohm's law: a 5 Ω resistor carries 2 A. What is the voltage across it?
• In a circuit with a dependent source, how would you determine the Thevenin resistance seen by the load?
• Which statement best describes the mesh-current method for a circuit with two meshes?
• A resistor with a movable contact that is adjusted by turning a shaft is called a(n) ? resistor.
• What term describes the opposition to the passage of magnetic flux lines?
• In a circuit with a dependent current source whose value is 2 I_x in parallel with a 5 Ω resistor, where I_x is the current through a 2 Ω resistor connected to the same node, how would you express I_x and set up the nodal equation?
• A mechanical device designed to allow or interrupt current flow in a circuit is called a ?
• In a circuit containing a dependent current source of value β times a voltage V across a resistor, how would you set up nodal equations?
• If current is 9 A and applied voltage is 27 V, what is the power?
• Voltage can be increased in a DC generator by increasing the ?
• In a series circuit, which statement is true about the current and voltage across components?
• Kirchhoff's Current Law describes what at a junction?
• Abbreviated with the capital letter K or the Greek letter ρ (rho), specific resistance is also called ?
• In a circuit with an open switch, the current will ?.
• When current flows to the intended destination through the load and back to the source, it is said to be ?
• What is a primary purpose of slip rings in the context of AC generation?
• Which pair of units correctly relates electrical quantities: voltage and current?
• When resistors are connected in series, their values are added to find total circuit resistance.
• In a 12 V source across a 4 Ω resistor, what is the current?
• How do Norton equivalents relate to Thevenin equivalents?
• In a Norton to Thevenin transformation, what are the relationships between I_N, V_th, and R_th?
• Electromagnetic fields are formed by combining ? and ?.
• For a Thevenin equivalent with V_th = 12 V and R_th = 2 Ω feeding a capacitor of 100 μF that is initially uncharged, what is the current through the circuit at the instant the capacitor is connected (t=0+)?
• A Thevenin equivalent with V_th = 9 V and R_th = 3 Ω feeds a 1 Ω load in series. What is the current through the load and the voltage across it?
• In a three-location switch arrangement, the configuration uses two 3-way switches and one 4-way switch.
• Define open-circuit voltage and explain its significance in Thevenin equivalents.
• In a series circuit, the sum of the voltages dropped across all components is equal to what?
• If R1 = 2 Ω and R2 = 10 Ω are connected in series, what is the total resistance?
• What is the orientation of the magnetic field relative to a straight conductor when current flows?
• In mesh analysis, how do you handle a current source that lies on a shared edge between two meshes?
• The variable letter 'E' in Ohm's Law stands for ?, and is measured in ?.
• In a circuit with a current source of 3 A in parallel with a 6 Ω resistor connected to a node, determine node voltage if the node also connects to a 12 Ω to ground.
• A circuit has a dependent voltage source equal to 0.5 times the voltage across a 4 Ω resistor in another branch. How would you incorporate this in nodal analysis?
• A 12 V source with two resistors in series (2 Ω and 8 Ω). Find the voltage across the 2 Ω resistor.
• In order to have voltage induced, there must be ? between the conductor and the magnetic field.
• In a parallel circuit with multiple paths for current, which statement correctly describes how the current through each path is determined?
• For a small circuit with open-circuit voltage 14 V and Thevenin resistance 7 Ω, if the load is 14 Ω, what is the voltage across the load?
• What is the SI unit used to measure electrical potential difference?
• When current returns to the source without flowing through the load, it is referred to as a(n) ?
• Using the Principle of Superposition, the total current in a circuit is equal to what?
• Which standard is primarily focused on electrical safety in the workplace?
• Convert 0.08 kilowatts to watts.
• When using node-voltage analysis with a voltage source connected between two non-reference nodes, what technique is commonly used?
• A Thevenin circuit has V_th = 24 V, R_th = 6 Ω. A load of 4 Ω is connected in series with the Thevenin source. What is the current through the load and the voltage across it?
• In a series circuit, which two quantities are directly proportional?
• If all resistors in parallel have the same value, then the total resistance is equal to the value of any one resistor divided by the total number of resistors.
• A circuit has a 5 V source in series with a 2 Ω resistor feeding a node that splits to a 4 Ω resistor and a 6 Ω resistor in parallel to ground. Compute the node voltage.
• After breaking down the circuit and solving for the total equivalent resistance, using the given applied voltage, the total current can be calculated with ...; then working back up through your redraws, the component current and voltage values can be determined.
• For N identical resistors in parallel, the total resistance is R divided by N.
• After thinking through the consolidation steps and redrawing the circuit to an equivalent resistor, the first step to solving a combination circuit is to calculate the ...
• Which quantity is described as the measure of opposition to current flow?
• The formula PT = ET × IT determines the total power consumption of the circuit when ... and ... are known.
• Why does a capacitor act as an open circuit to DC after a long time?
• In a series circuit, total resistance equals the sum of the individual resistances. Which statement is true about this property?
• For a series RC circuit with R=1 kΩ and C=1 μF charging from 0 V to 12 V, calculate τ and Vc after t=3τ.
• In the circuit with a 30 V source across 8 Ω and 12 Ω in parallel, what is the voltage across the 12 Ω resistor?
• Can Thevenin/Norton equivalents be used for circuits with dependent sources? If so, what must be preserved?
• In the United States, conductors are sized according to the ? standard.
• What is the equation Rt = Et / It used to solve for what quantity?
• Which fixed resistor can withstand more heat than any other type of resistor?
• Which phenomenon does the Left-Hand Rule for generators explain?
• A Δ network of 6 Ω between nodes A-B, 4 Ω B-C, and 12 Ω C-A is converted to a Y network. Which is Ra?
• In a circuit with a 60 V source and two resistors 10 Ω and 20 Ω in series, calculate total current and voltage drops across each resistor.
• In a parallel circuit, the total current is the sum of the currents in each branch.
• In the Left-Hand Rule for Generators, which finger indicates the current into the armature?
• If the applied voltage is 80 volts and the resistance is 20 ohms, what is the total current?
• Which particle carries a positive charge in an atom?
• Which formula gives power in a circuit using voltage and current?
• Common problems in electrical switches include all of the following except ?
• In switch terminology, which term describes the number of movable contact positions that determine how many circuits a switch can connect?
• A series circuit is a circuit where ...
• A DC generator creates a current that ? and an AC generator creates a current that ? .
• Increasing the current flowing through a conductor will ? the strength of the electromagnetic field around that conductor.
• What is the power when resistance is 22 ohms and applied voltage is 58 volts? Round to one decimal place.
• Which theorem states that any source can be reduced to a single equivalent voltage source in series with a resistor?
• Which equation correctly expresses the total current IT when the currents in all branches are known?
• How is Thevenin resistance R_th defined?
• In an atom, which particles have a negative charge, which have a positive charge, and which have no charge?
• The ohm is the measurement for the amount of what that exists in a circuit object?
• State the superposition principle and outline the steps to compute an output parameter in a circuit with two independent sources.
• Which theorem allows replacing a circuit with an equivalent voltage source in series with a resistor?
• In the delta-to-Y conversion, what is the sum Rab+Rbc+Rca?
• The variable letter 'P' in Watt's Law stands for ?, and is measured in ?.
• In an LR circuit with L = 200 mH and R = 50 Ω connected to a 24 V source, what is the steady-state current?
• In AC generators, what component is used instead of a commutator?
• In a series circuit, the total voltage is the sum of all the component voltages.
• If the voltage increases in a circuit while all other components stay the same, what happens to the circuit's power consumption?
• For an RC circuit with R = 1 kΩ and C = 1 μF, what is the time constant τ?
• In a Thevenin circuit with V_th = 12 V and R_th = 2 Ω feeding a short-circuited load (0 Ω), what is the current through the source immediately after connection?
• If a circuit has a resistance of 30 ohms and is supplied with 60 volts, what is the power?
• If a resistor in a parallel circuit has triple the resistance of a second resistor, its current is what fraction of the second resistor's current?
• In a discharge RC circuit with V0 = 5 V, R = 1 kΩ, and τ = 1 ms, what is Vc after t = 1 ms?
• According to Ohm's law for a lamp with fixed supply voltage, what happens to wattage as resistance increases?
• The Assumed Voltage formula is used when the source or branch voltage is not known and can be used to solve for the actual resistance total of the circuit.
• Which sequence correctly outlines the node-voltage method for circuits with multiple non-reference nodes?
• Given V = 50 V and R = 10 Ω, what is the current?
• The voltage applied to each load in parallel is equal to the total voltage.
• Which statement about a capacitor in a DC circuit after a long time is true?
• In a series circuit, the EN = IT × RN formula is used to determine the voltage drop across a component.
• From which pole do flux lines exit a magnet?
• Which statement best describes maximum power transfer for a Thevenin/Norton circuit?
• Which unit is the unit of power?
• Why does an inductor act as a short circuit in a direct current (DC) circuit after a long time?
• If the direction of the current flow changes, what else will change?
• In a parallel circuit, the total current is determined by the component currents being added.
• Perform a series-parallel reduction on a network: 6 Ω in series with parallel of 12 Ω and 3 Ω; then in series with a 9 Ω resistor and an 18 V source. Find the equivalent resistance of the parallel pair (12 Ω and 3 Ω).
• What is the total current in the circuit after the series-parallel reduction for the 18 V source scenario?
• What happens to current when a source splits into two or more paths?
• In the Left-Hand Rule for Conductors, the encircling fingers point in the direction of the ?
• In a mesh-current method with two meshes sharing an impedance, how is the shared impedance included in the KVL equations?
• Which two electrical ratings are commonly specified for lamps?
• Which equation represents Ohm's Law for current?
• Which component is used to start or stop current flow in a circuit?
• The entire applied voltage is dropped across each load in a parallel circuit.
• In a series circuit, which statement about current is true?
• Which equation correctly expresses the power dissipated in a resistor when current and resistance are known?
• Ferromagnetic materials are materials that ? .
• In a parallel circuit, the current through any resistor is related to the resistor's value by which relationship?
• An electromagnetic field is formed by combining electrostatic fields and magnetic fields.
• Which formula should be used to calculate wattage for a resistor when its resistance and current are known?
• In a parallel circuit, the voltage across each branch is equal to the supply voltage. Which statement is true?
• To determine when components in a circuit are in series or parallel, one should ?
• Which type of generator produces current that flows in a single direction?
• In a parallel circuit with 6 Ω and 3 Ω across a 9 V source, find total current and branch currents.
• A Thevenin equivalent is V_th = 24 V and R_th = 6 Ω. The load resistor R_L = 4 Ω is connected across the Thevenin source. What is the current through R_L and the voltage across it?
• If Et = 12 V and It = 3 A, Rt equals?
• What is the formula for the voltage drop across a load given current and resistance?
• In a circuit with fixed voltage, increasing a lamp's resistance will cause its wattage to
• How is a DC motor typically modeled in DC circuit analysis for steady-state?
• The equation 0 = ΣIin − ΣIout expresses which law?
• Lamps will have ratings for both ? and ?.
• The flux lines of a magnet leave the ? pole and enter the ? pole.
• Using Watt's Law, when solving for power, the current must be multiplied by the voltage.
• In a series circuit, the sum of the voltages across all components equals the source voltage.
• In an atom, which particle has positive charge, which has negative charge, and which has no charge?
• The correct formula for determining the total power consumption of the circuit when E (volts) and I (amps) are known is PT = ET × IT.
• A circuit where the voltage is the same across all components and equal to the supplied voltage is a ... circuit.
• Which equation correctly relates power, voltage, and current in a circuit?
• What is a Delta-to-Wye transformation and when is it used?
• In a series circuit, the source voltage equals the sum of the voltage drops; if the individual drops are 2 V, 3 V, and 5 V, what is the source voltage?
• A typical solution to control a lighting load from two locations is to employ a pair of ? switches.
• In DC steady-state, what is the behavior of capacitors and inductors?
• If a circuit is open, which of the following is true?
• If current is 12 A and voltage is 92 V, what is the power?
• Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL) are fundamental circuit laws. Which statement correctly describes them with a simple example?
• In DC steady-state, the impedance of an ideal capacitor as ω approaches zero is what?
• In the Left-Hand Rule for Conductors, the thumb indicates the direction of the current, and the encircling fingers indicate the direction of the ?
• What would create a stronger magnetic field?
• Electrical current described as flowing from the positive terminal of a battery through the circuit and back to the negative side of the battery is considered which type of current flow?
• In the Left-Hand Rule for Generators, which finger indicates the current induced into the armature?
• Which of the following is NOT a typical problem encountered with switches?
• In the node-voltage method, at which points are equations formed and which law is applied?
• If the load resistance in a Thevenin circuit with V_th = 9 V and R_th = 3 Ω is increased, what happens to the load current?
• For a capacitor of 50 μF connected across a 12 V DC source, what is the energy stored when fully charged?
• To determine V_th in Thevenin analysis, what is the first step?
• Reluctance is the opposition to what?
• What is the general expression for the energy stored in a capacitor in terms its capacitance C and voltage V?
• The formula E1 = Et × R1 / (R1 + R2) is known as which law?
• In a multi-location lighting circuit, what configuration includes three switches to control a single load?
• Delta-to-Wye transformation numeric example: Rab=6Ω, Rbc=3Ω, Rca=3Ω. Compute Ra, Rb, Rc.
• A 12 V source across two resistors in parallel: 6 Ω and 3 Ω. Find branch currents and total current.
• To find R_th, what must you do to the independent sources?
• What is the equivalent resistance of a 6 Ω resistor in parallel with a 3 Ω resistor?
• A 10 Ω resistor carries 2 A. What is the power dissipated, and what is the voltage across it?
• In a series-parallel network, some components are in series while others are in parallel.
• What is the unit for measuring resistance?
• In superposition, how do you handle multiple independent sources? Which sequence is correct?
• In Thevenin analysis with V_th = 18 V and R_th = 9 Ω, what is the short-circuit current I_sc?
• The motion of electrons in a conductor caused by the interaction between the magnetic field of a magnet and the magnetic field of the electrons causes a voltage to be ?
• Conventional current flow direction is from the positive terminal to the negative terminal.
• In DC steady-state, the impedance of an inductor as angular frequency ω approaches zero is what value?
• Determine the total voltage in a circuit when the current is 5 amps and the resistance is 45 ohms.
• In a series circuit, the current measured on the supply side of the load is equal to the current measured on the return path.
• Which formula expresses power using voltage and resistance?
• In a series circuit, if Resistor A has three times the resistance of Resistor B, the voltage across Resistor A will be what relative to the voltage across Resistor B?
• In a series circuit, the voltage drop across each component is proportional to its resistance. Which statement expresses this correctly?
• Thevenin's theorem describes the network as seen from the load terminals as which equivalent? (Thevenin equivalent consists of a voltage source V_th in series with resistance R_th; Steps: remove load to find V_th; zero independent sources and find R_th; draw V_th in series with R_th.)
• For a 6 V source in series with 4 Ω, determine V_th, R_th, I_N, and R_N.
• A 100 μF capacitor is charged to 9 V. What is the energy stored?
• A parallel circuit has multiple paths for current to flow.