DC Theory LMS Practice Test

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