Basic Electrical Theory Assessment Test

1. A meter used to measure both AC and DC voltage and current is known as which of the following:

An ohms meter

A multimeter

A resistance meter

None of the above

A multimeter is a meter that can measure both AC and DC voltage and current. It is a versatile tool used by electricians and technicians to troubleshoot electrical circuits and systems. It typically has multiple functions, including measuring voltage, current, resistance, and sometimes even capacitance and frequency. A multimeter is an essential tool for anyone working with electrical systems, as it allows for accurate and efficient measurements of various electrical parameters.

Explanation

A multimeter is a meter that can measure both AC and DC voltage and current. It is a versatile tool used by electricians and technicians to troubleshoot electrical circuits and systems. It typically has multiple functions, including measuring voltage, current, resistance, and sometimes even capacitance and frequency. A multimeter is an essential tool for anyone working with electrical systems, as it allows for accurate and efficient measurements of various electrical parameters.

2. Of all of the materials used for insulation, which of the following has the highest electrical breakdown strength and the longest life:

Rubber

Cloth

Impregnated paper

Colored vinyl

Rubber has the highest electrical breakdown strength and the longest life compared to the other materials listed. Rubber is a good insulator and can withstand high voltages without breaking down. It also has excellent durability and can last for a long time, making it a reliable choice for insulation.

Explanation

Rubber has the highest electrical breakdown strength and the longest life compared to the other materials listed. Rubber is a good insulator and can withstand high voltages without breaking down. It also has excellent durability and can last for a long time, making it a reliable choice for insulation.

3. Rearranging the control components in an electrical diagram in order to simplify tracing of a circuit is an example of a schematic diagram.

True

False

Rearranging the control components in an electrical diagram can indeed simplify tracing of a circuit. By rearranging the components in a logical and organized manner, it becomes easier to understand the flow of the circuit and identify any potential issues or errors. This can be especially helpful when troubleshooting or making modifications to the circuit. Therefore, it is accurate to say that rearranging the control components in an electrical diagram is an example of a schematic diagram.

Explanation

Rearranging the control components in an electrical diagram can indeed simplify tracing of a circuit. By rearranging the components in a logical and organized manner, it becomes easier to understand the flow of the circuit and identify any potential issues or errors. This can be especially helpful when troubleshooting or making modifications to the circuit. Therefore, it is accurate to say that rearranging the control components in an electrical diagram is an example of a schematic diagram.

4. Bonding safely conducts any fault currents which may arise.

True

False

Bonding is the process of connecting all metallic components of an electrical system together to create a safe path for fault currents. This helps to prevent electrical shocks and fires by ensuring that any fault currents are safely conducted away from people and equipment. Therefore, the statement that bonding safely conducts any fault currents is true.

Explanation

Bonding is the process of connecting all metallic components of an electrical system together to create a safe path for fault currents. This helps to prevent electrical shocks and fires by ensuring that any fault currents are safely conducted away from people and equipment. Therefore, the statement that bonding safely conducts any fault currents is true.

5. Electrical appliances shall be installed in parallel in order to make the operation of each appliance in- dependent of the others.

True

False

When electrical appliances are installed in parallel, each appliance receives the full voltage of the circuit independently of the others. This means that the operation of one appliance does not affect the operation of another. If one appliance fails, it does not interrupt the circuit path of the others. In contrast, if appliances were installed in series, the failure of one appliance would break the circuit and potentially stop the operation of all other appliances in the same circuit.

Explanation

When electrical appliances are installed in parallel, each appliance receives the full voltage of the circuit independently of the others. This means that the operation of one appliance does not affect the operation of another. If one appliance fails, it does not interrupt the circuit path of the others. In contrast, if appliances were installed in series, the failure of one appliance would break the circuit and potentially stop the operation of all other appliances in the same circuit.

6. In a 3Ø circuit, how many electrical degrees separate each phase:

3

120

180

360

In a 3-phase circuit, each phase is separated by 120 electrical degrees. This means that the phase angles of the three phases are evenly spaced apart by 120 degrees. This is important in understanding the relationship and timing between the different phases in a 3-phase system.

Explanation

In a 3-phase circuit, each phase is separated by 120 electrical degrees. This means that the phase angles of the three phases are evenly spaced apart by 120 degrees. This is important in understanding the relationship and timing between the different phases in a 3-phase system.

7. Some copper conductors are tinned to help prevent chemical reaction:

True

False

Copper conductors are sometimes tinned to prevent chemical reactions. Tinning involves coating the copper with a thin layer of tin. This layer acts as a barrier, preventing the copper from coming into direct contact with substances that could cause chemical reactions, such as moisture or corrosive materials. Tinning also improves the solderability of the copper, making it easier to join with other components. Overall, tinning helps to protect the copper conductor and maintain its performance and longevity.

Explanation

Copper conductors are sometimes tinned to prevent chemical reactions. Tinning involves coating the copper with a thin layer of tin. This layer acts as a barrier, preventing the copper from coming into direct contact with substances that could cause chemical reactions, such as moisture or corrosive materials. Tinning also improves the solderability of the copper, making it easier to join with other components. Overall, tinning helps to protect the copper conductor and maintain its performance and longevity.

8. Conductors are materials that can be charged by rubbing them against other wires.

True

False

Conductors are materials that allow the flow of electric charge. They can become charged through various methods such as induction or contact with a charged object, but not specifically by rubbing them against other wires. Therefore, the statement that conductors can be charged by rubbing them against other wires is false.

Explanation

Conductors are materials that allow the flow of electric charge. They can become charged through various methods such as induction or contact with a charged object, but not specifically by rubbing them against other wires. Therefore, the statement that conductors can be charged by rubbing them against other wires is false.

9. In order to change the rotation of a DC series motor, which of the following must be done:

The motor must be converted to AC.

F1 and F2 must be reversed.

The capacitor leads must be reversed.

The frequency must be altered.

To change the rotation of a DC series motor, reversing the connections of F1 and F2 is necessary. This is because the direction of current flow through the armature determines the direction of rotation. By reversing the connections, the current flow is reversed, resulting in a change in the motor's rotation. The other options mentioned, such as converting the motor to AC, reversing the capacitor leads, or altering the frequency, are not relevant to changing the rotation of a DC series motor.

Explanation

To change the rotation of a DC series motor, reversing the connections of F1 and F2 is necessary. This is because the direction of current flow through the armature determines the direction of rotation. By reversing the connections, the current flow is reversed, resulting in a change in the motor's rotation. The other options mentioned, such as converting the motor to AC, reversing the capacitor leads, or altering the frequency, are not relevant to changing the rotation of a DC series motor.

10. In an alternator, frequency is determined by which of the following?

Motor size

Rotation speed of the armature

Voltage

All of the above

The frequency in an alternator is determined by the rotation speed of the armature. As the armature rotates, it creates a changing magnetic field, which induces a voltage in the stator windings. The frequency of this voltage is directly proportional to the rotation speed of the armature. Therefore, by increasing or decreasing the rotation speed, the frequency of the alternator output can be adjusted. Motor size and voltage do not directly determine the frequency in an alternator.

Explanation

The frequency in an alternator is determined by the rotation speed of the armature. As the armature rotates, it creates a changing magnetic field, which induces a voltage in the stator windings. The frequency of this voltage is directly proportional to the rotation speed of the armature. Therefore, by increasing or decreasing the rotation speed, the frequency of the alternator output can be adjusted. Motor size and voltage do not directly determine the frequency in an alternator.

11. Two transmission wires create a corona when which of the following exists:

The wires have a high potential difference.

The wires are installed overlapping or too close together.

The wires are spaced too far apart.

None of the above

When transmission wires are installed overlapping or too close together, it creates a corona. The corona is a phenomenon that occurs when the electric field surrounding the wires ionizes the surrounding air molecules, causing a faint glow or hissing sound. This can lead to energy loss, increased electrical resistance, and interference with communication systems. Therefore, the installation of transmission wires in close proximity or overlapping can result in the occurrence of corona.

Explanation

When transmission wires are installed overlapping or too close together, it creates a corona. The corona is a phenomenon that occurs when the electric field surrounding the wires ionizes the surrounding air molecules, causing a faint glow or hissing sound. This can lead to energy loss, increased electrical resistance, and interference with communication systems. Therefore, the installation of transmission wires in close proximity or overlapping can result in the occurrence of corona.

12. The peak value of AC voltage determines the breakdown voltage of insulation.

True

False

The peak value of AC voltage refers to the maximum value that the voltage reaches during each cycle. The breakdown voltage of insulation is the voltage at which the insulation material fails and allows current to flow through it. Therefore, it is logical to conclude that the peak value of AC voltage determines the breakdown voltage of insulation.

Explanation

The peak value of AC voltage refers to the maximum value that the voltage reaches during each cycle. The breakdown voltage of insulation is the voltage at which the insulation material fails and allows current to flow through it. Therefore, it is logical to conclude that the peak value of AC voltage determines the breakdown voltage of insulation.

13. A metal halide lamp is also referred to as a quartz lamp.

True

False

A metal halide lamp is indeed referred to as a quartz lamp because it contains a quartz arc tube that is filled with metal halide gases. This type of lamp produces a bright white light and is commonly used in outdoor lighting, stadiums, and other applications where high-intensity lighting is required. The quartz material is used in the lamp because it can withstand the high temperatures generated by the arc discharge. Therefore, the statement "A metal halide lamp is also referred to as a quartz lamp" is true.

Explanation

A metal halide lamp is indeed referred to as a quartz lamp because it contains a quartz arc tube that is filled with metal halide gases. This type of lamp produces a bright white light and is commonly used in outdoor lighting, stadiums, and other applications where high-intensity lighting is required. The quartz material is used in the lamp because it can withstand the high temperatures generated by the arc discharge. Therefore, the statement "A metal halide lamp is also referred to as a quartz lamp" is true.

14. An incandescent lamp filament is made of nickel.

True

False

An incandescent lamp filament is not made of nickel. It is typically made of tungsten, which has a high melting point and can withstand the high temperatures required for the filament to glow and produce light. Nickel is not commonly used for incandescent lamp filaments because it has a lower melting point and would not be able to withstand the heat generated by the electric current passing through it.

Explanation

An incandescent lamp filament is not made of nickel. It is typically made of tungsten, which has a high melting point and can withstand the high temperatures required for the filament to glow and produce light. Nickel is not commonly used for incandescent lamp filaments because it has a lower melting point and would not be able to withstand the heat generated by the electric current passing through it.

15. The rate of flow of the electrical charges through a conductor is which of the following:

Watts

Ohms

Voltage

Current

The rate of flow of electrical charges through a conductor is referred to as current. Current is measured in units called amperes (A). It represents the amount of charge passing through a point in the circuit per unit time. Current is essential for the functioning of electrical devices as it provides the necessary energy for them to operate.

Explanation

The rate of flow of electrical charges through a conductor is referred to as current. Current is measured in units called amperes (A). It represents the amount of charge passing through a point in the circuit per unit time. Current is essential for the functioning of electrical devices as it provides the necessary energy for them to operate.

16. The most power lost in the form of heat would come from which of the following:

A short circuit

Resistance

“Z”

None of the above

Resistance is the correct answer because when current flows through a resistor, it encounters resistance which causes energy to be converted into heat. This heat is a form of power loss and is commonly known as Joule heating. In a short circuit, the resistance is very low, so the power loss in the form of heat is also low. The option "Z" is not explained, so it cannot be determined if it causes power loss. Therefore, resistance is the most likely source of power loss in the form of heat.

Explanation

Resistance is the correct answer because when current flows through a resistor, it encounters resistance which causes energy to be converted into heat. This heat is a form of power loss and is commonly known as Joule heating. In a short circuit, the resistance is very low, so the power loss in the form of heat is also low. The option "Z" is not explained, so it cannot be determined if it causes power loss. Therefore, resistance is the most likely source of power loss in the form of heat.

17. When reduced to the most nominal component, the smallest element of matter is which of the following:

One ohm of electrical current

An atom

Electrons

None of the above

Electrons are the smallest element of matter among the provided choices, as they are fundamental subatomic particles that are smaller than atoms and are crucial components of all matter.

Explanation

Electrons are the smallest element of matter among the provided choices, as they are fundamental subatomic particles that are smaller than atoms and are crucial components of all matter.

18. Which of the following terms is used to describe the inductive action, which causes current to flow on the outer surface of a conductor:

Halo Effect

Inductance

Skin effect

Insulated par value

Inductance is the correct term used to describe the inductive action that causes current to flow on the outer surface of a conductor. Inductance refers to the property of a conductor or circuit to oppose any change in the flow of current. When there is a change in current, an electromagnetic field is created, which induces a voltage that causes current to flow on the outer surface of the conductor. This phenomenon is known as skin effect, where the current is concentrated on the surface of the conductor rather than evenly distributed throughout its cross-section.

Explanation

Inductance is the correct term used to describe the inductive action that causes current to flow on the outer surface of a conductor. Inductance refers to the property of a conductor or circuit to oppose any change in the flow of current. When there is a change in current, an electromagnetic field is created, which induces a voltage that causes current to flow on the outer surface of the conductor. This phenomenon is known as skin effect, where the current is concentrated on the surface of the conductor rather than evenly distributed throughout its cross-section.

19. An electrical lighting timer switch is generally connected in parallel with the lighting.

True

False

An electrical lighting timer switch is generally connected in series with the lighting, not in parallel. When connected in series, the timer switch interrupts the flow of electricity to the lighting based on the programmed schedule. In contrast, connecting it in parallel would mean that the lighting would receive power regardless of the timer's settings, which defeats the purpose of having a timer switch.

Explanation

An electrical lighting timer switch is generally connected in series with the lighting, not in parallel. When connected in series, the timer switch interrupts the flow of electricity to the lighting based on the programmed schedule. In contrast, connecting it in parallel would mean that the lighting would receive power regardless of the timer's settings, which defeats the purpose of having a timer switch.

20. In order to calculate watt hours, which of the following formulas must be used:

E x I x T²

Amps/Volts

E x I x T

24 /(E x I x T )

Watt-hours, a measure of electrical energy consumption, are calculated by multiplying voltage (E), current (I), and time (T). This formula accounts for the product of electrical potential (voltage), the rate of flow of electric charge (current), and the duration of usage (time), providing a comprehensive measure of energy usage.

Explanation

Watt-hours, a measure of electrical energy consumption, are calculated by multiplying voltage (E), current (I), and time (T). This formula accounts for the product of electrical potential (voltage), the rate of flow of electric charge (current), and the duration of usage (time), providing a comprehensive measure of energy usage.

21. To connect an ammeter in series, must the circuit be opened at the voltage source and connected to the meter at the other end?

True

False

To connect an ammeter in series, the circuit does not need to be opened at the voltage source. Instead, the ammeter is connected in series with the other components of the circuit, allowing the current to flow through it. This allows the ammeter to measure the current passing through the circuit without interrupting the flow of current. Therefore, the statement is false.

Explanation

To connect an ammeter in series, the circuit does not need to be opened at the voltage source. Instead, the ammeter is connected in series with the other components of the circuit, allowing the current to flow through it. This allows the ammeter to measure the current passing through the circuit without interrupting the flow of current. Therefore, the statement is false.

22. A wiring system has two lengths of wires, where wire A has a resistance of 10 ohms and wire B is three times the length of wire A with two times the cross-sectional area, which means that resistance of wire B is equal to which of the following:

30 ohms

20 ohms

15 ohms

10 ohms

Explanation

23. If a transformer ratio is 20/1, then which of the following is true:

For every 20 turns in the primary, there is one turn in the secondary.

The primary voltage is 20 times greater than that of the secondary.

For every 20 rotations in the secondary, there is one rotation in the primary.

None of the above

The correct statement is: "For every 20 turns in the primary, there is one turn in the secondary." In a transformer, the turns ratio indicates the ratio of the number of turns in the primary coil to the number of turns in the secondary coil. In this case, a turns ratio of 20/1 means that for every 20 turns in the primary coil, there is one turn in the secondary coil. This ratio determines the relationship between the voltages in the primary and secondary circuits.

Explanation

The correct statement is: "For every 20 turns in the primary, there is one turn in the secondary." In a transformer, the turns ratio indicates the ratio of the number of turns in the primary coil to the number of turns in the secondary coil. In this case, a turns ratio of 20/1 means that for every 20 turns in the primary coil, there is one turn in the secondary coil. This ratio determines the relationship between the voltages in the primary and secondary circuits.

24. Ground fault protection for personnel on a 120 volt single-phase circuit is based on which of the following:

Ungrounded current between conductors

Unbalanced current between the grounded and ungrounded conductor

Overload in the current carrying conductor

Excessive voltage in the grounding conductor

Ground fault protection for personnel on a 120 volt single-phase circuit is based on the unbalanced current between the grounded and ungrounded conductor. This means that the protection system is designed to detect any difference in current flowing through the two conductors. If there is an imbalance, it indicates that some current is flowing through an unintended path, such as through a person or the ground, and the protection system will quickly interrupt the circuit to prevent electric shock. This type of protection is crucial for ensuring the safety of individuals working with electrical systems.

Explanation

Ground fault protection for personnel on a 120 volt single-phase circuit is based on the unbalanced current between the grounded and ungrounded conductor. This means that the protection system is designed to detect any difference in current flowing through the two conductors. If there is an imbalance, it indicates that some current is flowing through an unintended path, such as through a person or the ground, and the protection system will quickly interrupt the circuit to prevent electric shock. This type of protection is crucial for ensuring the safety of individuals working with electrical systems.

25. What is the equivalent of resistance among the following options in an open circuit?

0.012 ohms

1 coulomb

Zero

Infinity

An open circuit means there is no continuous path for current to flow, resulting in infinite resistance. Since current cannot pass through an open circuit, resistance becomes effectively unmeasurable and infinitely large. This is a fundamental electrical property and a common concept in circuit analysis. None of the other options accurately represent the resistance of an open circuit.

Explanation

An open circuit means there is no continuous path for current to flow, resulting in infinite resistance. Since current cannot pass through an open circuit, resistance becomes effectively unmeasurable and infinitely large. This is a fundamental electrical property and a common concept in circuit analysis. None of the other options accurately represent the resistance of an open circuit.

26. A negative charge will do which of the following: I. Interact with negative charges II. Interact with positive charges III. Cause a short in a positive system

I & III

I & II

I only

All of the above

A negative charge will interact with negative charges (I) because like charges repel each other. It will also interact with positive charges (II) because opposite charges attract each other. However, it will not cause a short in a positive system (III) as a short circuit occurs when there is an unintended path for current to flow, usually due to a break or fault in the circuit.

Explanation

A negative charge will interact with negative charges (I) because like charges repel each other. It will also interact with positive charges (II) because opposite charges attract each other. However, it will not cause a short in a positive system (III) as a short circuit occurs when there is an unintended path for current to flow, usually due to a break or fault in the circuit.

27. If a transformer has a voltage step-down from 117 volts to 6 volts then the ratio of the transformer is equal to which of the following:

19.5 :1

1 :19.5

180 :1

3 :1

To find the ratio of the transformer, we divide the primary voltage by the secondary voltage:

Ratio = Primary Voltage / Secondary Voltage

Given: Primary Voltage (Vp) = 117 volts Secondary Voltage (Vs) = 6 volts

Ratio = Vp / Vs Ratio = 117 / 6 Ratio ≈ 19.5

So, the ratio of the transformer is approximately 19.5:1.

Explanation

To find the ratio of the transformer, we divide the primary voltage by the secondary voltage:

Ratio = Primary Voltage / Secondary Voltage

Given: Primary Voltage (Vp) = 117 volts Secondary Voltage (Vs) = 6 volts

Ratio = Vp / Vs Ratio = 117 / 6 Ratio ≈ 19.5

So, the ratio of the transformer is approximately 19.5:1.

28. Frequency is measured in which of the following:

Voltage

Watts

Hertz

None of the above

Frequency is a measure of how many cycles or oscillations occur in a given time period. It is commonly used to describe the number of times an electrical signal or wave completes a full cycle in one second. The unit used to measure frequency is Hertz (Hz), which represents one cycle per second. Therefore, the correct answer is Hertz.

Explanation

Frequency is a measure of how many cycles or oscillations occur in a given time period. It is commonly used to describe the number of times an electrical signal or wave completes a full cycle in one second. The unit used to measure frequency is Hertz (Hz), which represents one cycle per second. Therefore, the correct answer is Hertz.

29. For electroplating power, which of the following generators should be used?

Separately excited

Delta system

Split phase

None of the above

A separately excited generator provides a stable and controlled output voltage, which is essential for electroplating. Electroplating requires precise voltage and current levels to ensure uniform coating quality. These generators allow independent adjustment of the field winding, enabling consistent operation even under varying load conditions, making them ideal for such applications.

Explanation

A separately excited generator provides a stable and controlled output voltage, which is essential for electroplating. Electroplating requires precise voltage and current levels to ensure uniform coating quality. These generators allow independent adjustment of the field winding, enabling consistent operation even under varying load conditions, making them ideal for such applications.

30. Which of the following is not applicable to an AC system?

It cannot be transformed.

It develops eddy currents.

It can interfere with communications lines.

It is suitable for charging batteries.

AC systems can be transformed using transformers to change the voltage level, which is a key advantage of AC over DC systems. This transformation is not applicable to DC systems. Therefore, the statement "It can not be transformed" is not applicable to an AC system.

Explanation

AC systems can be transformed using transformers to change the voltage level, which is a key advantage of AC over DC systems. This transformation is not applicable to DC systems. Therefore, the statement "It can not be transformed" is not applicable to an AC system.

31. Power factor is equal to which of the following:

Apparent power multiplied by true power

True power divided by apparent power

Watts multiplied by amps

None of the above

The power factor (PF) is the ratio of true power (measured in watts) to apparent power (measured in volt-amperes). It represents the efficiency of electrical power usage, where a PF of 1 indicates maximum efficiency. Mathematically, PF = True Power / Apparent Power. A high PF signifies efficient energy utilization with minimal losses.

Explanation

The power factor (PF) is the ratio of true power (measured in watts) to apparent power (measured in volt-amperes). It represents the efficiency of electrical power usage, where a PF of 1 indicates maximum efficiency. Mathematically, PF = True Power / Apparent Power. A high PF signifies efficient energy utilization with minimal losses.

32. Where the current flow through a conductor is greatest will be the point where the voltage drop is the lowest.

True

False

The statement is false. The point where the current flow through a conductor is greatest will likely experience the highest voltage drop, not the lowest. This is due to the relationship described by Ohm's law, which states that voltage (V) is equal to the product of current (I) and resistance (R), represented by the equation V = IR. When the current is high and resistance remains constant, the voltage drop across the conductor will also be high.

Explanation

The statement is false. The point where the current flow through a conductor is greatest will likely experience the highest voltage drop, not the lowest. This is due to the relationship described by Ohm's law, which states that voltage (V) is equal to the product of current (I) and resistance (R), represented by the equation V = IR. When the current is high and resistance remains constant, the voltage drop across the conductor will also be high.

33. If a motor enclosure is designed to contain sparks or flashes that could ignite surrounding vapors or gases, then the enclosure is considered to be which of the following:

Ventilated

Explosion proof

Explosion resistant

Fire proof

An enclosure designed to contain sparks or flashes that could ignite surrounding vapors or gases is termed "explosion-proof." These enclosures prevent ignition by confining sparks within the enclosure, minimizing the risk of explosions in hazardous environments where flammable gases or vapors are present.

Explanation

An enclosure designed to contain sparks or flashes that could ignite surrounding vapors or gases is termed "explosion-proof." These enclosures prevent ignition by confining sparks within the enclosure, minimizing the risk of explosions in hazardous environments where flammable gases or vapors are present.

34. Which of the following materials is used on conduits inside and outside of a box:

Bushings

Couplings

Lock nuts

All of the above

Couplings are the correct answer because they are used on conduits both inside and outside of a box. Couplings are fittings that connect two sections of conduit together, allowing for a secure and continuous pathway for electrical wires. They are commonly used in electrical installations to join conduit sections and provide a means of pulling wires through the conduit. Therefore, couplings are essential components for maintaining the integrity and functionality of conduits inside and outside of a box.

Explanation

Couplings are the correct answer because they are used on conduits both inside and outside of a box. Couplings are fittings that connect two sections of conduit together, allowing for a secure and continuous pathway for electrical wires. They are commonly used in electrical installations to join conduit sections and provide a means of pulling wires through the conduit. Therefore, couplings are essential components for maintaining the integrity and functionality of conduits inside and outside of a box.

35. Electromagnetic induction involves a substance becoming a magnet when it is placed next to another magnet.

True

False

Electromagnetic induction does not involve a substance becoming a magnet when it is placed next to another magnet. Instead, it refers to the process of generating an electric current in a conductor by changing the magnetic field around it. This can be achieved by moving a magnet near a conductor or by changing the current in a nearby conductor.

Explanation

Electromagnetic induction does not involve a substance becoming a magnet when it is placed next to another magnet. Instead, it refers to the process of generating an electric current in a conductor by changing the magnetic field around it. This can be achieved by moving a magnet near a conductor or by changing the current in a nearby conductor.

36. A three horsepower motor is equivalent to which of the following in watts:

2238.48 watts.

3000 watts

None of the above

746 watts

One horsepower is defined as 746 watts in the mechanical (imperial) system. Therefore, to convert three horsepower to watts, you simply multiply:

3 horsepower × 746 watts/horsepower = 2238 watts (more precisely, 2238.48 watts).

This conversion is standard in physics and engineering, particularly when comparing motor or engine outputs across different unit systems. Understanding this helps bridge imperial and metric measurements, especially in global contexts where watts (SI units) are the standard for measuring power output.

Explanation

One horsepower is defined as 746 watts in the mechanical (imperial) system. Therefore, to convert three horsepower to watts, you simply multiply:

3 horsepower × 746 watts/horsepower = 2238 watts (more precisely, 2238.48 watts).

This conversion is standard in physics and engineering, particularly when comparing motor or engine outputs across different unit systems. Understanding this helps bridge imperial and metric measurements, especially in global contexts where watts (SI units) are the standard for measuring power output.

37. The sum of series voltage drops equals the applied voltage.

True

False

The statement is false because the sum of series voltage drops does not always equal the applied voltage. In a series circuit, the total voltage across the circuit is equal to the sum of the individual voltage drops across each component. Therefore, the sum of the series voltage drops is always less than or equal to the applied voltage.

Explanation

The statement is false because the sum of series voltage drops does not always equal the applied voltage. In a series circuit, the total voltage across the circuit is equal to the sum of the individual voltage drops across each component. Therefore, the sum of the series voltage drops is always less than or equal to the applied voltage.

38. A wire secured at one end with the other end fastened to a pole under tension is known as which of the following:

Messenger wire

A service drop

A guy wire

None of the above

A wire secured at one end with the other end fastened to a pole under tension is known as a service drop. A service drop is commonly used in electrical installations to deliver power from a utility pole to a building or structure. It is typically made of insulated conductors and is responsible for providing electricity to the premises. Messenger wire is used to support other wires, while a guy wire is used to provide stability to structures like poles or towers. Therefore, neither of these options accurately describes the given scenario.

Explanation

A wire secured at one end with the other end fastened to a pole under tension is known as a service drop. A service drop is commonly used in electrical installations to deliver power from a utility pole to a building or structure. It is typically made of insulated conductors and is responsible for providing electricity to the premises. Messenger wire is used to support other wires, while a guy wire is used to provide stability to structures like poles or towers. Therefore, neither of these options accurately describes the given scenario.

39. In order to correct a low power factor, which of the following should be checked first?

Resistance

Watts

Inductive load

All of the above

To correct a low power factor, the first thing that should be checked is the inductive load. Inductive loads, such as motors and transformers, can cause a lagging power factor. By reducing the inductive load or using power factor correction devices, the power factor can be improved. Resistance and watts do not directly affect the power factor, so they would not be the first things to check in this case.

Explanation

To correct a low power factor, the first thing that should be checked is the inductive load. Inductive loads, such as motors and transformers, can cause a lagging power factor. By reducing the inductive load or using power factor correction devices, the power factor can be improved. Resistance and watts do not directly affect the power factor, so they would not be the first things to check in this case.

40. What does it cost per year (at 8 cents per kWh) for the power loss of a 12 AWG circuit conductor (100ft long) that has a total resistance of 0.40 ohms and a current flow of 16A? (Approx)

$300.16

$71.76

$170.6

$190.3

Here's how to calculate the approximate cost per year of the power loss in the conductor:

Calculate Power Loss:

We know the formula for power loss (P) in a conductor: P = I² * R

P = (16A)² * 0.40Ω = 102.4 watts (W)

Convert Power Loss to kWh per year:

We need to convert watts (instantaneous power) to kilowatt-hours (kWh), considering the power loss happens throughout the year. We'll assume the circuit is operational continuously for this estimation.

Hours per year: 365 days/year * 24 hours/day = 8760 hours/year

Energy loss (kWh) = Power loss (W) * Time (hours) / 1000 (conversion factor)

Energy loss (kWh) = 102.4 W * 8760 hours/year / 1000 = 897.024 kWh/year (approximately)

Calculate Cost per Year:

Cost per kWh = $0.08

Annual Cost = Energy loss (kWh) * Cost per kWh

Annual Cost = 897.024 kWh/year * $0.08/kWh = $71.76 (approximately)

Therefore, the estimated cost per year for the power loss in the conductor is $71.76.

Note: This is an approximation based on the assumptions of continuous operation and a constant current flow. In reality, the actual cost may vary depending on the usage pattern of the circuit.

Explanation

Here's how to calculate the approximate cost per year of the power loss in the conductor:

Calculate Power Loss:

We know the formula for power loss (P) in a conductor: P = I² * R

P = (16A)² * 0.40Ω = 102.4 watts (W)

Convert Power Loss to kWh per year:

We need to convert watts (instantaneous power) to kilowatt-hours (kWh), considering the power loss happens throughout the year. We'll assume the circuit is operational continuously for this estimation.

Hours per year: 365 days/year * 24 hours/day = 8760 hours/year

Energy loss (kWh) = Power loss (W) * Time (hours) / 1000 (conversion factor)

Energy loss (kWh) = 102.4 W * 8760 hours/year / 1000 = 897.024 kWh/year (approximately)

Calculate Cost per Year:

Cost per kWh = $0.08

Annual Cost = Energy loss (kWh) * Cost per kWh

Annual Cost = 897.024 kWh/year * $0.08/kWh = $71.76 (approximately)

Therefore, the estimated cost per year for the power loss in the conductor is $71.76.

Note: This is an approximation based on the assumptions of continuous operation and a constant current flow. In reality, the actual cost may vary depending on the usage pattern of the circuit.

41. The armature reaction in an alternator is magnetizing at lagging loads.

True

False

The armature reaction in an alternator is not magnetizing at lagging loads. Armature reaction refers to the effect of the magnetic field produced by the armature current on the main magnetic field. At lagging loads, the armature reaction is demagnetizing, meaning it weakens the main magnetic field. Therefore, the correct answer is false.

Explanation

The armature reaction in an alternator is not magnetizing at lagging loads. Armature reaction refers to the effect of the magnetic field produced by the armature current on the main magnetic field. At lagging loads, the armature reaction is demagnetizing, meaning it weakens the main magnetic field. Therefore, the correct answer is false.

42. The temperature of the area surrounding a conductor is known as the ambient temperature.

True

False

Ambient temperature refers to the temperature of the surrounding environment or the immediate area around an object, in this case, a conductor. In the context of electrical conductors and devices, ambient temperature is an important factor because it can affect the performance and characteristics of the conductor. For example, the resistance of a conductor may vary with temperature, and the conductor's ability to dissipate heat depends on the ambient temperature.

Explanation

Ambient temperature refers to the temperature of the surrounding environment or the immediate area around an object, in this case, a conductor. In the context of electrical conductors and devices, ambient temperature is an important factor because it can affect the performance and characteristics of the conductor. For example, the resistance of a conductor may vary with temperature, and the conductor's ability to dissipate heat depends on the ambient temperature.

43. In order to adjust the voltage of a constant speed DC generator, the field voltage must be changed.

True

False

In order to adjust the voltage of a constant speed DC generator, the field voltage does not need to be changed. The voltage of a constant speed DC generator can be adjusted by changing the load resistance or by using a voltage regulator. The field voltage controls the strength of the magnetic field, which affects the generator's output voltage, but it is not the only factor that can be adjusted to change the voltage.

Explanation

In order to adjust the voltage of a constant speed DC generator, the field voltage does not need to be changed. The voltage of a constant speed DC generator can be adjusted by changing the load resistance or by using a voltage regulator. The field voltage controls the strength of the magnetic field, which affects the generator's output voltage, but it is not the only factor that can be adjusted to change the voltage.

44. If the power factor of a circuit is increased, then which of the following occurs:

The active power is increased.

The reactive power is decreased.

Both of the above

None of the above

When the power factor of a circuit is increased, it means that the circuit becomes more efficient in converting electrical power into useful work. This is because the power factor is a measure of how effectively the circuit uses the available power. A higher power factor indicates that there is less reactive power in the circuit, which means that the circuit is drawing less current from the power source. As a result, the reactive power is decreased, leading to a more efficient utilization of electrical power. Therefore, the correct answer is that the reactive power is decreased.

Explanation

When the power factor of a circuit is increased, it means that the circuit becomes more efficient in converting electrical power into useful work. This is because the power factor is a measure of how effectively the circuit uses the available power. A higher power factor indicates that there is less reactive power in the circuit, which means that the circuit is drawing less current from the power source. As a result, the reactive power is decreased, leading to a more efficient utilization of electrical power. Therefore, the correct answer is that the reactive power is decreased.

45. The wattage rating of a resistor determines its ability to absorb heat.

True

False

The wattage rating of a resistor does not determine its ability to absorb heat. The wattage rating of a resistor actually determines its power handling capacity, which is the amount of power it can safely dissipate without overheating. The ability to absorb heat is determined by the thermal conductivity and design of the resistor, not its wattage rating.

Explanation

The wattage rating of a resistor does not determine its ability to absorb heat. The wattage rating of a resistor actually determines its power handling capacity, which is the amount of power it can safely dissipate without overheating. The ability to absorb heat is determined by the thermal conductivity and design of the resistor, not its wattage rating.

46. If a series circuit has unequal resistances throughout the circuit, then which of the following is true:

The lowest resistance has the highest current.

The lowest resistance has the highest voltage.

The highest resistance has the highest voltage.

The highest resistance has the highest current.

In a series circuit, the current remains the same throughout all components. According to Ohm's law (V = IR), voltage is directly proportional to resistance. Therefore, in a series circuit with unequal resistances, the component with the highest resistance will have the highest voltage drop. So, the correct statement is:

The highest resistance has the highest voltage.

Explanation

In a series circuit, the current remains the same throughout all components. According to Ohm's law (V = IR), voltage is directly proportional to resistance. Therefore, in a series circuit with unequal resistances, the component with the highest resistance will have the highest voltage drop. So, the correct statement is:

The highest resistance has the highest voltage.

47. Electric motors operate on the principal of induction and repulsion.

True

False

Electric motors operate on the principle of electromagnetic induction, not induction and repulsion. Induction is the process by which a changing magnetic field induces an electric current in a conductor, which is the basic principle behind the operation of electric motors. Repulsion, on the other hand, refers to the force between two like charges or magnetic poles, which is not the principle that electric motors rely on. Therefore, the statement is false.

Explanation

Electric motors operate on the principle of electromagnetic induction, not induction and repulsion. Induction is the process by which a changing magnetic field induces an electric current in a conductor, which is the basic principle behind the operation of electric motors. Repulsion, on the other hand, refers to the force between two like charges or magnetic poles, which is not the principle that electric motors rely on. Therefore, the statement is false.

48. Inductance and capacitance are not considerations in a DC current for which of the following reasons:

DC supply has no frequency

DC supply carries power equally

Both of the above

None of the above

Inductance and capacitance are not considerations in a DC current because DC supply has no frequency. In AC circuits, inductance and capacitance play a significant role as they cause impedance and affect the flow of current. However, in DC circuits, the current flows in one direction without any change in direction or frequency, making inductance and capacitance irrelevant. Additionally, the DC supply carries power equally, meaning it delivers a constant amount of power throughout the circuit, further eliminating the need for inductance and capacitance considerations.

Explanation

Inductance and capacitance are not considerations in a DC current because DC supply has no frequency. In AC circuits, inductance and capacitance play a significant role as they cause impedance and affect the flow of current. However, in DC circuits, the current flows in one direction without any change in direction or frequency, making inductance and capacitance irrelevant. Additionally, the DC supply carries power equally, meaning it delivers a constant amount of power throughout the circuit, further eliminating the need for inductance and capacitance considerations.

49. In a generator, voltage is produced by which of the following conditions:

Electrical pressure

Vibration

Magnetism

Cutting lines of force

Voltage is produced in a generator by cutting lines of force. This refers to the process of moving a conductor, such as a wire, through a magnetic field. As the conductor cuts across the magnetic field lines, an electromotive force (EMF) is induced, which results in the generation of voltage. This phenomenon is known as electromagnetic induction and is the fundamental principle behind the operation of generators.

Explanation

Voltage is produced in a generator by cutting lines of force. This refers to the process of moving a conductor, such as a wire, through a magnetic field. As the conductor cuts across the magnetic field lines, an electromotive force (EMF) is induced, which results in the generation of voltage. This phenomenon is known as electromagnetic induction and is the fundamental principle behind the operation of generators.

50. Because of conductor resistance, flux leakage, eddy currents, and hysteresis losses, not all of the input power is transferred to the secondary winding for useful purposes.

True

False

The statement in the question suggests that there are various losses in a transformer, including conductor resistance, flux leakage, eddy currents, and hysteresis losses. These losses result in a decrease in the amount of input power that is transferred to the secondary winding for useful purposes. Therefore, the correct answer is False, as it contradicts the explanation provided.

Explanation

The statement in the question suggests that there are various losses in a transformer, including conductor resistance, flux leakage, eddy currents, and hysteresis losses. These losses result in a decrease in the amount of input power that is transferred to the secondary winding for useful purposes. Therefore, the correct answer is False, as it contradicts the explanation provided.

51. In applications where high starting torque is required, DC series motors are generally used.

True

False

DC series motors are not generally used in applications where high starting torque is required. Instead, DC shunt or compound motors are typically used in such applications. DC series motors have a characteristic of high starting torque, but they also have the tendency to overspeed when the load is removed. Therefore, they are not suitable for applications where high starting torque is required.

Explanation

DC series motors are not generally used in applications where high starting torque is required. Instead, DC shunt or compound motors are typically used in such applications. DC series motors have a characteristic of high starting torque, but they also have the tendency to overspeed when the load is removed. Therefore, they are not suitable for applications where high starting torque is required.

52. In a coil, the higher the level of self-inductance:

The lower the level of resistance will be

The longer the delay will be in establishing current through it

The greater the level of flux produced will be

None of the above

The higher the level of self-inductance in a coil, the longer the delay will be in establishing current through it. This is because self-inductance is a property of a coil that opposes changes in current. When the level of self-inductance is higher, the coil resists changes in current more, resulting in a longer delay in establishing current through it.

Explanation

The higher the level of self-inductance in a coil, the longer the delay will be in establishing current through it. This is because self-inductance is a property of a coil that opposes changes in current. When the level of self-inductance is higher, the coil resists changes in current more, resulting in a longer delay in establishing current through it.

53. Circuits that are run in series:

Have a total voltage of 8.92 per circuit

Have a total resistance equal to the sum of all the resistors

Must be connected to a bonding jumper

All of the above

The correct statement regarding circuits that are run in series is: Have a total resistance equal to the sum of all the resistors. When circuits are connected in series, the total resistance is indeed equal to the sum of the individual resistances in the circuit. This is a fundamental characteristic of series circuits.

Explanation

The correct statement regarding circuits that are run in series is: Have a total resistance equal to the sum of all the resistors. When circuits are connected in series, the total resistance is indeed equal to the sum of the individual resistances in the circuit. This is a fundamental characteristic of series circuits.

54. Illumination is measured in which of the following units:

Light per square inch

Foot candles

Lumens

None of the above

Illumination, the amount of light reaching a surface, is typically measured in lumens. Lumens quantify the total amount of visible light emitted by a source, providing a standard unit for comparing brightness. Foot candles, another unit of measurement, express illuminance—the amount of light falling on a surface—as perceived by the human eye. However, lumens offer a more direct measure of emitted light. Light per square inch is not a standard unit for illumination measurement. Therefore, the correct answer is "Lumens."

Explanation

Illumination, the amount of light reaching a surface, is typically measured in lumens. Lumens quantify the total amount of visible light emitted by a source, providing a standard unit for comparing brightness. Foot candles, another unit of measurement, express illuminance—the amount of light falling on a surface—as perceived by the human eye. However, lumens offer a more direct measure of emitted light. Light per square inch is not a standard unit for illumination measurement. Therefore, the correct answer is "Lumens."

55. Which of the following should be tested to check for voltage to ground?

From the breaker to the grounding neutral

From hot to neutral

From a breaker to the cabinet

All of the above

To check for voltage to ground, it is necessary to test the voltage between the hot wire and the neutral wire. This is because the hot wire carries the current and the neutral wire acts as the return path for the current. By measuring the voltage between these two wires, one can determine if there is any voltage present with respect to ground. Testing the voltage from the breaker to the grounding neutral or from a breaker to the cabinet may not provide accurate information about the voltage to ground. Therefore, the correct option is to test from hot to neutral.

Explanation

To check for voltage to ground, it is necessary to test the voltage between the hot wire and the neutral wire. This is because the hot wire carries the current and the neutral wire acts as the return path for the current. By measuring the voltage between these two wires, one can determine if there is any voltage present with respect to ground. Testing the voltage from the breaker to the grounding neutral or from a breaker to the cabinet may not provide accurate information about the voltage to ground. Therefore, the correct option is to test from hot to neutral.

56. If there are three resistors in a series circuit, labeled R1, R2, and R3, with a total power used of 225 watts, and the individual power used by R2 is 75 watts and by R3 is 100 watts,then the power used by resistor R1 is which of the following:

100 watts

75 watts

50 watts

25 watts

In a series circuit with three resistors (R1, R2, and R3) and a total power consumption of 225 watts, we can find the power used by resistor R1 by subtracting the known power used by resistors R2 and R3 from the total power.

Total Power (P_total) = 225 watts Power used by R2 (P2) = 75 watts Power used by R3 (P3) = 100 watts

Using the formula for total power in a series circuit:

P_total = P1 + P2 + P3

We want to find P1 (the power used by R1):

225 watts = P1 + 75 watts + 100 watts

Solving for P1:

P1 = 225 watts - 75 watts - 100 watts P1 = 50 watts

Therefore, the power used by resistor R1 is 50 watts.

Explanation

In a series circuit with three resistors (R1, R2, and R3) and a total power consumption of 225 watts, we can find the power used by resistor R1 by subtracting the known power used by resistors R2 and R3 from the total power.

Total Power (P_total) = 225 watts Power used by R2 (P2) = 75 watts Power used by R3 (P3) = 100 watts

Using the formula for total power in a series circuit:

P_total = P1 + P2 + P3

We want to find P1 (the power used by R1):

225 watts = P1 + 75 watts + 100 watts

Solving for P1:

P1 = 225 watts - 75 watts - 100 watts P1 = 50 watts

Therefore, the power used by resistor R1 is 50 watts.

57. An eddy current can cause which of the following:

Power fluctuation

Unusable frequency ranges

An increase in core loss

All of the above

Eddy currents are circulating currents that are induced in a conductor when it is exposed to a changing magnetic field. These currents can cause an increase in core loss in magnetic materials. As the eddy currents flow through the material, they generate heat due to resistance, leading to energy loss in the form of core loss. Therefore, an increase in core loss is a possible effect of eddy currents.

Explanation

Eddy currents are circulating currents that are induced in a conductor when it is exposed to a changing magnetic field. These currents can cause an increase in core loss in magnetic materials. As the eddy currents flow through the material, they generate heat due to resistance, leading to energy loss in the form of core loss. Therefore, an increase in core loss is a possible effect of eddy currents.

58. A centimeter is equal to which of the following:

0.3937 inches

Inches X 2.54

1.98 inches

None of the above

To convert 1 centimeter to inches, you can use the conversion factor that 1 inch is approximately equal to 2.54 centimeters.

So, to find the equivalent in inches, you can use the fraction:

1 cm * (1 inch / 2.54 cm) = 1/2.54 inches

So, 1 centimeter is approximately equal to 1/2.54 inches, which can also be expressed as approximately 0.3937 inches when rounded to four decimal places.

Explanation

To convert 1 centimeter to inches, you can use the conversion factor that 1 inch is approximately equal to 2.54 centimeters.

So, to find the equivalent in inches, you can use the fraction:

1 cm * (1 inch / 2.54 cm) = 1/2.54 inches

So, 1 centimeter is approximately equal to 1/2.54 inches, which can also be expressed as approximately 0.3937 inches when rounded to four decimal places.

59. What is the approximate power consumed by a 10 kW heat strip rated 230V, when connected to a 208V circuit?

8 kW

9 kW

11 kW

12 kW

The power of the heat strip will be less because the Applied voltage (208V) is less than equipment voltage Rating (230V). To calculate this, we must determine the Heat strip resistance rating at 230V, and then determine The power rating at 208V base on the heat strip resist- Ance rating. P= E²/R E = Applied Voltage = 208V R = Resistance of Heat Strip = E²/P Heat Strip Voltage Rating = 230V Power Rating of Heat Strip = 10,000W Resistance of Heat Strip= 230V²/10,000W Resistance of Heat Strip= 5.29 ohms P = E²/R P = (208V x 208V)/5.29 ohms P = 43,624/5.29 ohms P = 8,178W/1,000 = 8.2 kW

Explanation

The power of the heat strip will be less because the Applied voltage (208V) is less than equipment voltage Rating (230V). To calculate this, we must determine the Heat strip resistance rating at 230V, and then determine The power rating at 208V base on the heat strip resist- Ance rating. P= E²/R E = Applied Voltage = 208V R = Resistance of Heat Strip = E²/P Heat Strip Voltage Rating = 230V Power Rating of Heat Strip = 10,000W Resistance of Heat Strip= 230V²/10,000W Resistance of Heat Strip= 5.29 ohms P = E²/R P = (208V x 208V)/5.29 ohms P = 43,624/5.29 ohms P = 8,178W/1,000 = 8.2 kW

60. When a switch on a 110 amp system is closed, the total resistance of the switch is equal to which of the following:

55 amps

220 volts

1100 ohms

Zero

In electrical circuits, when a switch is closed (assuming it is an ideal switch with negligible resistance when closed), it effectively creates a path with zero resistance. This allows current to flow through the circuit without impedance from the switch itself. Therefore, the total resistance of the closed switch would be considered negligible or zero in practical terms.

Explanation

In electrical circuits, when a switch is closed (assuming it is an ideal switch with negligible resistance when closed), it effectively creates a path with zero resistance. This allows current to flow through the circuit without impedance from the switch itself. Therefore, the total resistance of the closed switch would be considered negligible or zero in practical terms.

61. Which of the following is characteristic of inductance?

It creates opposition to voltage.

It opposes changes in current.

It creates changes in current.

None of the above

Inductance is a property of an electrical circuit that creates opposition to changes in current. When the current in a circuit changes, inductance generates a counter electromotive force (EMF) that opposes this change. This opposition to changes in current is known as inductive reactance. Therefore, the correct answer is "It opposes changes in current."

Explanation

Inductance is a property of an electrical circuit that creates opposition to changes in current. When the current in a circuit changes, inductance generates a counter electromotive force (EMF) that opposes this change. This opposition to changes in current is known as inductive reactance. Therefore, the correct answer is "It opposes changes in current."

62. Efficiency is calculated as output divided by useful input.

True

False

The efficiency is not calculated as output divided by input. Efficiency is actually calculated as output divided by the total input, which includes both useful and wasted input. Therefore, the given statement is false.

Explanation

The efficiency is not calculated as output divided by input. Efficiency is actually calculated as output divided by the total input, which includes both useful and wasted input. Therefore, the given statement is false.

63. A motor that draws 4.5 kilowatts from the power line and delivers 5 horsepower has an efficiency equal to which of the following:

90.5 percent

83 percent

75 percent

45 percent

The efficiency of a motor can be calculated by dividing the output power by the input power and multiplying by 100. In this case, the motor delivers 5 horsepower, which is equivalent to 3.73 kilowatts (1 horsepower = 0.746 kilowatts). The input power is given as 4.5 kilowatts. Dividing the output power by the input power and multiplying by 100 gives an efficiency of approximately 82.89 percent, which is closest to 83 percent.

Explanation

The efficiency of a motor can be calculated by dividing the output power by the input power and multiplying by 100. In this case, the motor delivers 5 horsepower, which is equivalent to 3.73 kilowatts (1 horsepower = 0.746 kilowatts). The input power is given as 4.5 kilowatts. Dividing the output power by the input power and multiplying by 100 gives an efficiency of approximately 82.89 percent, which is closest to 83 percent.

64. Lightning protection is intended to protect the building structure itself, as well as the electrical equipment on or inside the building structure.

True

False

Lightning protection is primarily designed to safeguard the building structure from lightning strikes, diverting the electrical current safely into the ground. However, it does not directly protect the electrical equipment inside the building. To protect electrical equipment, additional measures such as surge protectors or grounding systems are required. Therefore, the statement provided is false.

Explanation

Lightning protection is primarily designed to safeguard the building structure from lightning strikes, diverting the electrical current safely into the ground. However, it does not directly protect the electrical equipment inside the building. To protect electrical equipment, additional measures such as surge protectors or grounding systems are required. Therefore, the statement provided is false.

65. What is the nameplate FLA for a 20 hp, 208V, three-phase motor with 90 percent power factor and 80 percent efficiency?

51A

80A

65A

57.52A

The nameplate Full Load Amps (FLA) for a 20 hp, 208V, three-phase motor with a 90 percent power factor and 80 percent efficiency is approximately 62.12 amps.

Explanation

The nameplate Full Load Amps (FLA) for a 20 hp, 208V, three-phase motor with a 90 percent power factor and 80 percent efficiency is approximately 62.12 amps.

66. In a transformer, the side with more turns is which of the following:

The high voltage side

The primary

The secondary

The low voltage side

In a transformer, the voltage is directly related to the number of turns in the coil. The greater the number of turns, the higher the voltage on that side. This is based on the transformer principle that voltage ratio equals the turns ratio. So, if one side has more turns than the other, it will handle a higher voltage. Therefore, the side with more turns is always the high voltage side, whether it's the primary or the secondary winding.

Explanation

In a transformer, the voltage is directly related to the number of turns in the coil. The greater the number of turns, the higher the voltage on that side. This is based on the transformer principle that voltage ratio equals the turns ratio. So, if one side has more turns than the other, it will handle a higher voltage. Therefore, the side with more turns is always the high voltage side, whether it's the primary or the secondary winding.

67. The amperage of a three-phase system can be calculated as which of the following:

Watts divided by the value of the voltage times 1.73

1.73 X watts divided by volts

Volts times 1.73

Power factor divided by the value of the voltage times 1.73

The amperage (current) of a three-phase system can be calculated using the formula:

I = P / (√3 × V × PF)

So, out of the options provided, the correct one is: Watts divided by the value of the voltage times 1.73. This formula takes into account the power consumed in watts, the voltage, and the square root of 3 (√3 or approximately 1.73) to calculate the current (amperage) in a three-phase system.

Explanation

The amperage (current) of a three-phase system can be calculated using the formula:

I = P / (√3 × V × PF)

So, out of the options provided, the correct one is: Watts divided by the value of the voltage times 1.73. This formula takes into account the power consumed in watts, the voltage, and the square root of 3 (√3 or approximately 1.73) to calculate the current (amperage) in a three-phase system.

68. Arcing is defined as a luminous discharge of electricity across an insulating medium. Electric arcs operate at temperatures between and expel small particles of very hot molten materials.

1,000 and 5,000°F

2,000 and 10,000°F

5,000 and 15,000°F

10,000 and 25,000°F

Electric arcs operate at temperatures between 5,000 and 15,000°F. This high-temperature range is a characteristic feature of the arcing process, which involves a luminous discharge of electricity across an insulating medium. The intense heat generated by the arc can cause the surrounding materials to melt and vaporize, leading to the expulsion of small particles of hot molten materials.

Explanation

Electric arcs operate at temperatures between 5,000 and 15,000°F. This high-temperature range is a characteristic feature of the arcing process, which involves a luminous discharge of electricity across an insulating medium. The intense heat generated by the arc can cause the surrounding materials to melt and vaporize, leading to the expulsion of small particles of hot molten materials.

69. A capacitor performs which of the following functions:

It opposes changes in voltage.

It generators voltage.

It creates changes in amperage.

None of the above

A capacitor stores electrical energy in an electric field and opposes changes in voltage across its plates. This property allows capacitors to smooth out voltage fluctuations in circuits. Capacitors do not generate voltage, nor do they directly create changes in amperage; instead, they regulate voltage by charging and discharging.

Explanation

A capacitor stores electrical energy in an electric field and opposes changes in voltage across its plates. This property allows capacitors to smooth out voltage fluctuations in circuits. Capacitors do not generate voltage, nor do they directly create changes in amperage; instead, they regulate voltage by charging and discharging.

70. The circuit conductors between service equipment and the final branch circuit overcurrent device are considered to be which of the following:

Service laterals

Feeder conductors

Grounded conductors

A wire assembly

The circuit conductors between service equipment and the final branch circuit overcurrent device are considered to be service laterals. Service laterals are the conductors that connect the service equipment, such as the main panel or meter, to the branch circuit overcurrent device, which is typically a circuit breaker or fuse. These conductors carry the electrical current from the service equipment to the branch circuits in a building or structure.

Explanation

The circuit conductors between service equipment and the final branch circuit overcurrent device are considered to be service laterals. Service laterals are the conductors that connect the service equipment, such as the main panel or meter, to the branch circuit overcurrent device, which is typically a circuit breaker or fuse. These conductors carry the electrical current from the service equipment to the branch circuits in a building or structure.

71. Three parallel circuits with a voltage of 150 volts each, with a resistance of 5 ohms, produce a total current of which of the following:

90 volts

150 volts

225 volts

450 volts

Calculate the current in each circuit:

Ohm's Law: Current (I) = Voltage (V) / Resistance (R)

I = 150 volts / 5 ohms = 30 amps

Calculate the total current:

Since the circuits are parallel, the total current is the sum of the currents in each circuit.

Total current = 30 amps + 30 amps + 30 amps = 90 amps

Explanation

Calculate the current in each circuit:

Ohm's Law: Current (I) = Voltage (V) / Resistance (R)

I = 150 volts / 5 ohms = 30 amps

Calculate the total current:

Since the circuits are parallel, the total current is the sum of the currents in each circuit.

Total current = 30 amps + 30 amps + 30 amps = 90 amps

72. The output of a 3-phase transformer is measured in which of the following units:

Volts

Amperes

Volt-amps

Watts

The output of a 3-phase transformer is measured in Amperes because Amperes represent the current flowing through the transformer. The output current is an important parameter to determine the power transfer capability of the transformer and to ensure that the load is supplied with the required amount of current. Volts represent the voltage, Volt-amps represent the apparent power, and Watts represent the real power, but these units do not directly measure the output of a 3-phase transformer.

Explanation

The output of a 3-phase transformer is measured in Amperes because Amperes represent the current flowing through the transformer. The output current is an important parameter to determine the power transfer capability of the transformer and to ensure that the load is supplied with the required amount of current. Volts represent the voltage, Volt-amps represent the apparent power, and Watts represent the real power, but these units do not directly measure the output of a 3-phase transformer.

73. If a two-wire 120 volt circuit has one grounded conductor and supplies a single-phase 5 horsepower motor, then the required number of overloads is which of the following:

Two, one in each conductor

One in the grounded conductor

One in the ungrounded conductor

Zero, no overload is required

In a two-wire 120 volt circuit with one grounded conductor, the motor is single-phase and has a power of 5 horsepower. Since the motor is single-phase and not three-phase, it does not require any overloads. Overloads are typically used to protect against excessive current in three-phase motors, but in this case, the motor does not require any overload protection. Therefore, the required number of overloads is zero.

Explanation

In a two-wire 120 volt circuit with one grounded conductor, the motor is single-phase and has a power of 5 horsepower. Since the motor is single-phase and not three-phase, it does not require any overloads. Overloads are typically used to protect against excessive current in three-phase motors, but in this case, the motor does not require any overload protection. Therefore, the required number of overloads is zero.

74. Which of the following conductor types is both moisture and heat resistant?

THHN

THW

XHHW

None of the above

XHHW is the correct answer because it is a type of conductor that is designed to be both moisture and heat resistant. XHHW stands for Cross-Linked High Heat Water-resistant, indicating that it has been specially treated to withstand exposure to moisture and high temperatures. This makes XHHW a suitable choice for applications where the conductor may be exposed to harsh environmental conditions. THHN and THW are not specifically designed to be moisture and heat resistant, so they are not the correct answer.

Explanation

XHHW is the correct answer because it is a type of conductor that is designed to be both moisture and heat resistant. XHHW stands for Cross-Linked High Heat Water-resistant, indicating that it has been specially treated to withstand exposure to moisture and high temperatures. This makes XHHW a suitable choice for applications where the conductor may be exposed to harsh environmental conditions. THHN and THW are not specifically designed to be moisture and heat resistant, so they are not the correct answer.

75. A balanced 3-wire, 120/240V, single-phase circuit is connected so that the ungrounded conductors are from different transformer phases (Line 1 and Line 2). The current on the grounded conductor will be of the ungrounded conductor current.

0%

70%

80%

100%

In a balanced 3-wire, 120/240V, single-phase circuit where the ungrounded conductors are from different transformer phases, the current on the grounded conductor will be equal to the current on the ungrounded conductor. This is because in a balanced circuit, the current flowing out of one ungrounded conductor will be equal to the current flowing into the other ungrounded conductor, resulting in a balanced flow of current. Therefore, the current on the grounded conductor will also be 100% of the current on the ungrounded conductor.

Explanation

In a balanced 3-wire, 120/240V, single-phase circuit where the ungrounded conductors are from different transformer phases, the current on the grounded conductor will be equal to the current on the ungrounded conductor. This is because in a balanced circuit, the current flowing out of one ungrounded conductor will be equal to the current flowing into the other ungrounded conductor, resulting in a balanced flow of current. Therefore, the current on the grounded conductor will also be 100% of the current on the ungrounded conductor.

76. In a lamp holder, which of the following is true of the grounded conductor?

It would connect to the screw shell.

It is the lead wire.

It would be fire-retardant.

All of the above

In a lamp holder, the following is true of the grounded conductor:

It would connect to the screw shell.

The grounded conductor, often referred to as the "neutral" wire in electrical circuits, is typically connected to the screw shell or metal casing of the lamp holder. This connection helps to provide a safe path for electrical current and prevent electrical shock hazards.

Explanation

In a lamp holder, the following is true of the grounded conductor:

It would connect to the screw shell.

The grounded conductor, often referred to as the "neutral" wire in electrical circuits, is typically connected to the screw shell or metal casing of the lamp holder. This connection helps to provide a safe path for electrical current and prevent electrical shock hazards.

77. Temperature is converted from Celsius to Fahrenheit by using which of the following Equations:

Dividing the Centigrade temperature by 1.8

(Temp C X 1.8) + 32

Multiplying the Centigrade temperature by 32 and adding 1.798

None of the above

To convert a temperature from Celsius to Fahrenheit, you can use the equation (Celsius temperature × 1.8) + 32. This formula involves multiplying the Celsius temperature by 1.8 and then adding 32 to get the equivalent temperature in Fahrenheit. It is a standard method for temperature conversion between the Celsius and Fahrenheit scales.

Explanation

To convert a temperature from Celsius to Fahrenheit, you can use the equation (Celsius temperature × 1.8) + 32. This formula involves multiplying the Celsius temperature by 1.8 and then adding 32 to get the equivalent temperature in Fahrenheit. It is a standard method for temperature conversion between the Celsius and Fahrenheit scales.

78. What size transformer is required for a 100A, 240V, single-phase noncontinuous load that has a power factor of 85 percent?

15 kVA

25 kVA

37.5 kVA

50kVA

Transformer kVA = (Volts x Amperes)/1,000 Transformer kVA = (240V x 100A)/1,000 Transformer kVA = 24 Note: Transformers should be sized using the apparent power, which is VA = E x I.

Explanation

Transformer kVA = (Volts x Amperes)/1,000 Transformer kVA = (240V x 100A)/1,000 Transformer kVA = 24 Note: Transformers should be sized using the apparent power, which is VA = E x I.

79. Magnetic lines of force are also known as which of the following:

Flux

Alternating currents

Direct currents

None of the above

Magnetic lines of force represent the direction and strength of a magnetic field and are commonly referred to as magnetic flux. Alternating currents (AC) and direct currents (DC) pertain to types of electrical currents, not magnetic field representations. Therefore, "Flux" is the correct term associated with magnetic lines of force.

Explanation

Magnetic lines of force represent the direction and strength of a magnetic field and are commonly referred to as magnetic flux. Alternating currents (AC) and direct currents (DC) pertain to types of electrical currents, not magnetic field representations. Therefore, "Flux" is the correct term associated with magnetic lines of force.

80. Lamp holders installed in damp or wet locations shall be which of the following:

Waterproof

Insulated

Brass

None of the above

Lamp holders in damp or wet locations must be waterproof to prevent moisture from reaching electrical components. Waterproofing helps reduce risks such as electrical shock and short circuits, ensuring safety. Properly sealed lamp holders block moisture infiltration, which is crucial in environments prone to high humidity or water exposure. Non-waterproof or poorly insulated holders can compromise safety and lead to equipment failure. Using waterproof fixtures aligns with safety codes and standards, providing both longevity and reliability in adverse conditions. Hence, "Waterproof" is the correct answer.

Explanation

Lamp holders in damp or wet locations must be waterproof to prevent moisture from reaching electrical components. Waterproofing helps reduce risks such as electrical shock and short circuits, ensuring safety. Properly sealed lamp holders block moisture infiltration, which is crucial in environments prone to high humidity or water exposure. Non-waterproof or poorly insulated holders can compromise safety and lead to equipment failure. Using waterproof fixtures aligns with safety codes and standards, providing both longevity and reliability in adverse conditions. Hence, "Waterproof" is the correct answer.

81. What is the conductor power loss in watts for a 120V circuit that has a 3% voltage drop and carries a current flow of 12A?

43.2 W

86W

172W

1,440W

The conductor power loss is caused by resistance in the wire, resulting in voltage drop. When a 120V circuit has a 3% voltage drop, it loses 3.6V across the conductor. This lost voltage multiplied by the current (12A) gives the power dissipated as heat: 3.6V × 12A = 43.2W. This calculation is based on Ohm's Law and the power formula (P = V × I), making 43.2 watts the correct and precise measurement of conductor loss in this scenario.

Explanation

The conductor power loss is caused by resistance in the wire, resulting in voltage drop. When a 120V circuit has a 3% voltage drop, it loses 3.6V across the conductor. This lost voltage multiplied by the current (12A) gives the power dissipated as heat: 3.6V × 12A = 43.2W. This calculation is based on Ohm's Law and the power formula (P = V × I), making 43.2 watts the correct and precise measurement of conductor loss in this scenario.

82. Which of the following is used to control speed in a DC motor?

Field winding

A primary transformer

Ground fault breaker

A bonding jumper

Field winding is used to control the speed of a DC motor. By varying the strength of the magnetic field produced by the field winding, the speed of the motor can be controlled. This is typically achieved by adjusting the field current through the winding, either manually or automatically, using a controller.

Explanation

Field winding is used to control the speed of a DC motor. By varying the strength of the magnetic field produced by the field winding, the speed of the motor can be controlled. This is typically achieved by adjusting the field current through the winding, either manually or automatically, using a controller.

83. The electrical property of conductors that allows them to oppose the free flow of current traveling over them is measured in which of the following:

Amperes

Ohms

Volts

Watts

Ohms measure electrical resistance, the property of conductors that opposes the flow of electric current. This opposition occurs because materials resist the movement of electrons to varying degrees. Higher resistance means less current flows for a given voltage. Understanding resistance, measured in ohms, is crucial in designing and analyzing electrical circuits.

Explanation

Ohms measure electrical resistance, the property of conductors that opposes the flow of electric current. This opposition occurs because materials resist the movement of electrons to varying degrees. Higher resistance means less current flows for a given voltage. Understanding resistance, measured in ohms, is crucial in designing and analyzing electrical circuits.

84. The efficiency of electrical equipment is determined by which of the following:

The amount of friction present

The motor speed divided by the input power

The power output divided by the input

None of the above

The efficiency of electrical equipment is determined by the ratio of the motor speed to the input power. This is because efficiency is a measure of how effectively the equipment converts input power into useful output power. A higher motor speed relative to the input power indicates that the equipment is operating more efficiently, as it is able to produce more output power with the given input. Conversely, a lower motor speed relative to the input power suggests that the equipment is less efficient, as it is not able to convert the input power into as much useful output power.

Explanation

The efficiency of electrical equipment is determined by the ratio of the motor speed to the input power. This is because efficiency is a measure of how effectively the equipment converts input power into useful output power. A higher motor speed relative to the input power indicates that the equipment is operating more efficiently, as it is able to produce more output power with the given input. Conversely, a lower motor speed relative to the input power suggests that the equipment is less efficient, as it is not able to convert the input power into as much useful output power.

85. Based on the figure below, the voltage across the 5 amp load after the neutral is opened, if both loads have resistance and the power factor is 1.0, would be which of the following:

240 volts

180 volts

150 volts

Cannot be determined

When the neutral is opened, the circuit becomes a series configuration, and the current remains constant. However, without specific resistance values for the loads, the voltage drop across each load cannot be calculated. Since the total voltage is shared between the resistors, the individual voltage depends on their resistances. The problem does not provide enough data to determine the voltage across the 5A load accurately. Therefore, "Cannot be determined" is the correct answer.

Explanation

When the neutral is opened, the circuit becomes a series configuration, and the current remains constant. However, without specific resistance values for the loads, the voltage drop across each load cannot be calculated. Since the total voltage is shared between the resistors, the individual voltage depends on their resistances. The problem does not provide enough data to determine the voltage across the 5A load accurately. Therefore, "Cannot be determined" is the correct answer.

86. Bonding does which of the following:

Provides electrical continuity

Regulates the voltage

Controls the load on the system installation

All of the above

Bonding refers to the process of connecting conductive materials to ensure electrical continuity and reduce the risk of electrical shock. By bonding, the load on the system installation can be controlled, as it helps to distribute the electrical load evenly and prevent overloading. Bonding also helps regulate the voltage by providing a pathway for the flow of electrical current. Therefore, the correct answer is "Controls the load on the system installation."

Explanation

Bonding refers to the process of connecting conductive materials to ensure electrical continuity and reduce the risk of electrical shock. By bonding, the load on the system installation can be controlled, as it helps to distribute the electrical load evenly and prevent overloading. Bonding also helps regulate the voltage by providing a pathway for the flow of electrical current. Therefore, the correct answer is "Controls the load on the system installation."

87. If a circuit breaker is installed vertically and the handle is flipped up, then the circuit breaker will be which of the following:

Off

Unable to operate properly

On

Locked in place

When a circuit breaker is installed vertically and the handle is flipped up, it means that the circuit breaker is in the "on" position. In this position, the circuit breaker is locked in place and cannot be operated further. This is because flipping the handle up completes the circuit and allows the flow of electricity. The locked position ensures that the circuit breaker remains in the "on" state and prevents accidental switching off.

Explanation

When a circuit breaker is installed vertically and the handle is flipped up, it means that the circuit breaker is in the "on" position. In this position, the circuit breaker is locked in place and cannot be operated further. This is because flipping the handle up completes the circuit and allows the flow of electricity. The locked position ensures that the circuit breaker remains in the "on" state and prevents accidental switching off.

88. Based on Ohm's law, the voltage of a system is equal to which of the following:

Current multiplied by the wattage

Current multiplied by the resistance

Amperes divided by the resistance

Amperes multiplied by the current

Based on Ohm's law, the voltage (V) of a system is equal to the product of the current (I) flowing through the system and the resistance (R) of the system. This relationship can be expressed by the formula: V=I*R. In other words, voltage is directly proportional to current and resistance. This fundamental law is named after the German physicist Georg Simon Ohm and is a key principle in understanding electrical circuits and their behavior.

Explanation

Based on Ohm's law, the voltage (V) of a system is equal to the product of the current (I) flowing through the system and the resistance (R) of the system. This relationship can be expressed by the formula: V=I*R. In other words, voltage is directly proportional to current and resistance. This fundamental law is named after the German physicist Georg Simon Ohm and is a key principle in understanding electrical circuits and their behavior.

89. During one complete rotation of 360 degrees, a three-phase 6-pole AC 34 kVA alternator on a Y- connected system will have how many cycles:

4

3

18

12

During one complete rotation of a 6-pole AC alternator, there will be 6 cycles of current. In a Y-connected system, each cycle will be counted as one cycle, so the total number of cycles will be 6. However, since the question is asking for the number of cycles during one complete rotation of 360 degrees, we need to divide the total number of cycles by 360 degrees. Therefore, the alternator will have 6/360 = 1/60 of a cycle per degree. Since there are 360 degrees in a complete rotation, the alternator will have 360*(1/60) = 6 cycles during one complete rotation. Hence, the correct answer is 4.

Explanation

During one complete rotation of a 6-pole AC alternator, there will be 6 cycles of current. In a Y-connected system, each cycle will be counted as one cycle, so the total number of cycles will be 6. However, since the question is asking for the number of cycles during one complete rotation of 360 degrees, we need to divide the total number of cycles by 360 degrees. Therefore, the alternator will have 6/360 = 1/60 of a cycle per degree. Since there are 360 degrees in a complete rotation, the alternator will have 360*(1/60) = 6 cycles during one complete rotation. Hence, the correct answer is 4.

90. In a 100 volt circuit with a resistance of 25 ohms, the current flowing through the circuit is which of the following:

1.25 amps

2.5 amps

4 amps

5 amps

The current flowing through a circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is 100 volts and the resistance is 25 ohms. Therefore, the current flowing through the circuit is 100 volts divided by 25 ohms, which equals 4 amps.

Explanation

The current flowing through a circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is 100 volts and the resistance is 25 ohms. Therefore, the current flowing through the circuit is 100 volts divided by 25 ohms, which equals 4 amps.

91. What is the power consumed by a 10 kW heat strip rated 230V connected to a 115V circuit?

2.5 kW

5 kW

7.5 kW

15 kW

The power of the heat strip will be less because the applied voltage (115V) is less than the equipment voltage rating (230V). To calculate this, we must determine the heat strip resistance rating at 230V, and then determine the power rating at 115V based on the heat strip resist- ance rating. P= E2/R E = Applied Voltage = 115V R = Resistance of Heat Strip = E2/P Heat Strip Voltage Rating = 230V Power Rating of Heat Strip = 10,000W Resistance of Heat Strip = 230V2/10,000W Resistance of Heat Strip = 5.29 ohms P = 13,225/5.29 ohms P = 2,500W/1,000 P=2.5kW Note: Power changes with the square of the voltage. If the voltage is reduced to 50%, then the power consumed will be equal to the new voltage percent2 or 50%2, or 10,000 x (0.50×0.50 = 0.25 = 25%) = 2,500W

Explanation

The power of the heat strip will be less because the applied voltage (115V) is less than the equipment voltage rating (230V). To calculate this, we must determine the heat strip resistance rating at 230V, and then determine the power rating at 115V based on the heat strip resist- ance rating. P= E2/R E = Applied Voltage = 115V R = Resistance of Heat Strip = E2/P Heat Strip Voltage Rating = 230V Power Rating of Heat Strip = 10,000W Resistance of Heat Strip = 230V2/10,000W Resistance of Heat Strip = 5.29 ohms P = 13,225/5.29 ohms P = 2,500W/1,000 P=2.5kW Note: Power changes with the square of the voltage. If the voltage is reduced to 50%, then the power consumed will be equal to the new voltage percent2 or 50%2, or 10,000 x (0.50×0.50 = 0.25 = 25%) = 2,500W

92. Two equally valued resistors in series have a total resistance of which of the following:

Twice as much as one of the resistors

Half of one

The difference between each resistance

None of the above

When resistors are connected in series, their total resistance is the sum of their individual resistances. If two resistors have the same resistance value (R), their total resistance in series would be R + R = 2R, which is twice the value of one resistor.

Explanation

When resistors are connected in series, their total resistance is the sum of their individual resistances. If two resistors have the same resistance value (R), their total resistance in series would be R + R = 2R, which is twice the value of one resistor.

93. The combined opposition to current by resistance and reactance is which of the following:

“Z”

Impedance

Both of the above

None of the above

Impedance, denoted as "Z," represents the total opposition to current flow in an electrical circuit, combining the effects of resistance and reactance. It encompasses both resistance to the flow of direct current and reactance, which accounts for opposition to alternating current due to capacitance or inductance.

Explanation

Impedance, denoted as "Z," represents the total opposition to current flow in an electrical circuit, combining the effects of resistance and reactance. It encompasses both resistance to the flow of direct current and reactance, which accounts for opposition to alternating current due to capacitance or inductance.

94. The power factor for a single-phase 50 amp 100 volt electric motor that draws 25 watts is which of the following:

20

0.20

0.025

0.005

The power factor for an electric motor is the ratio of the real power (in watts) to the apparent power (in volt-amperes). In this case, the motor draws 25 watts of real power and operates at 100 volts and 50 amps. The apparent power can be calculated by multiplying the voltage and current, which gives 100 volts * 50 amps = 5000 volt-amperes. Therefore, the power factor is 25 watts / 5000 volt-amperes = 0.005.

Explanation

The power factor for an electric motor is the ratio of the real power (in watts) to the apparent power (in volt-amperes). In this case, the motor draws 25 watts of real power and operates at 100 volts and 50 amps. The apparent power can be calculated by multiplying the voltage and current, which gives 100 volts * 50 amps = 5000 volt-amperes. Therefore, the power factor is 25 watts / 5000 volt-amperes = 0.005.

95. In a transformer, the voltage per turn in the primary relates to the voltage per turn in the secondary in which of the following ways:

The primary is more.

The secondary is more.

They are the same.

None of the above

In a transformer, the voltage per turn in the primary coil is directly proportional to the voltage per turn in the secondary coil. This relationship holds true for an ideal transformer, where the turns ratio remains constant, resulting in equivalent voltage per turn in both the primary and secondary coils.

Explanation

In a transformer, the voltage per turn in the primary coil is directly proportional to the voltage per turn in the secondary coil. This relationship holds true for an ideal transformer, where the turns ratio remains constant, resulting in equivalent voltage per turn in both the primary and secondary coils.

96. A resistor's ability to absorb heat is gauged in which of the following units:

Watts

Ohms

Volts

Amps

The ability of a resistor to absorb heat is not measured in amps. Amps (amperes) measure the flow of electric current, not the heat absorption capacity. The correct unit to measure the heat absorption capacity of a resistor is watts. Watts measure the rate of energy transfer or power, which includes the conversion of electrical energy into heat energy. Therefore, the correct answer is Watts.

Explanation

The ability of a resistor to absorb heat is not measured in amps. Amps (amperes) measure the flow of electric current, not the heat absorption capacity. The correct unit to measure the heat absorption capacity of a resistor is watts. Watts measure the rate of energy transfer or power, which includes the conversion of electrical energy into heat energy. Therefore, the correct answer is Watts.

97. Watts are equal to which of the following:

Voltage divided by amps

Amps multiplied by voltage times the power factor

Ohms multiplied by amps and divided by the power factor

None of the above

The correct answer is "None of the above" because watts are equal to the product of voltage and current, not divided by or multiplied by any other factors. The formula for calculating watts is P = VI, where P is power in watts, V is voltage in volts, and I is current in amps. So, none of the given options accurately represents the relationship between watts, voltage, and current.

Explanation

The correct answer is "None of the above" because watts are equal to the product of voltage and current, not divided by or multiplied by any other factors. The formula for calculating watts is P = VI, where P is power in watts, V is voltage in volts, and I is current in amps. So, none of the given options accurately represents the relationship between watts, voltage, and current.

98. A dielectric electrical element is which of the following:

A capacitor

A grounding conductor

An insulator

None of the above

A dielectric electrical element refers to a material that can be inserted between the plates of a capacitor to increase its capacitance. It acts as an insulator, preventing the flow of direct current while allowing the passage of alternating current. A grounding conductor, on the other hand, is used to connect electrical systems or equipment to the ground to prevent electrical shock. An insulator is a material that does not conduct electricity. Therefore, none of the given options accurately describe a dielectric electrical element.

Explanation

A dielectric electrical element refers to a material that can be inserted between the plates of a capacitor to increase its capacitance. It acts as an insulator, preventing the flow of direct current while allowing the passage of alternating current. A grounding conductor, on the other hand, is used to connect electrical systems or equipment to the ground to prevent electrical shock. An insulator is a material that does not conduct electricity. Therefore, none of the given options accurately describe a dielectric electrical element.

99. Three-phase wye-connected systems can overheat because of circulating odd triple harmonic currents.

2-wire

3-wire

4-wire

None of these

The statement is incorrect. Three-phase wye-connected systems can experience overheating due to circulating odd triple harmonic currents. However, these circulating currents typically occur in delta-connected systems, not wye-connected systems. Therefore, the correct answer is: none of these.

Explanation

The statement is incorrect. Three-phase wye-connected systems can experience overheating due to circulating odd triple harmonic currents. However, these circulating currents typically occur in delta-connected systems, not wye-connected systems. Therefore, the correct answer is: none of these.

100. According the Kirchhoff's current law, electrical current will do which of the following in Parallel circuits:

Combine in the parallel path

Divide and flow through each parallel path

Increase in voltage

Experience a voltage drop

According to Kirchhoff's current law, in parallel circuits, the total current entering the circuit will divide and flow through each parallel path. As a result, each parallel path will experience a voltage drop, which is why the correct answer is "Experience a voltage drop."

Explanation

According to Kirchhoff's current law, in parallel circuits, the total current entering the circuit will divide and flow through each parallel path. As a result, each parallel path will experience a voltage drop, which is why the correct answer is "Experience a voltage drop."