DC Theory LMS Practice Test

These questions are part of the practice quiz. Start practicing

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