1.
In DC calculations, you must use a power factor
Correct Answer
B. False
Explanation
dc calculations there is no concern about power factor
2.
DC systems have to include an additional rectifier/charger if redundancy is required.
Correct Answer
A. True
Explanation
In DC systems, redundancy refers to having a backup or duplicate component in case of failure. In order to achieve redundancy, an additional rectifier/charger is required. This additional component ensures that there is a backup power source available in case the primary rectifier/charger fails. Therefore, the statement is true.
3.
Direct current is:
Correct Answer
B. Unidirectional
Explanation
Direct current refers to the flow of electric charge in one direction only. Unlike alternating current, which constantly changes direction, direct current flows steadily and consistently in a single direction. Therefore, the correct answer is "Unidirectional."
4.
Direct current changes polarity
Correct Answer
B. False
Explanation
does not change polarity
5.
What are the two types of power board distribution
Correct Answer(s)
A. Centralized distribution
C. Decentralized distribution
Explanation
The two types of power board distribution are centralized distribution and decentralized distribution. Centralized distribution refers to a system where power is distributed from a central location to multiple points. Decentralized distribution, on the other hand, involves distributing power from multiple sources to different locations. Both types of distribution have their own advantages and disadvantages depending on the specific needs and requirements of the situation.
6.
What devices incorporate two or more conditioning and protection methods
Correct Answer
C. Power line conditioners
Explanation
Power line conditioners are devices that incorporate two or more conditioning and protection methods. They are designed to improve the quality of electrical power by regulating voltage levels, filtering out harmonics, and protecting against power surges and fluctuations. These devices are commonly used in industrial and commercial settings to ensure stable and reliable power supply to sensitive equipment and machinery.
7.
What is used to reduce the voltage waveform distortion
Correct Answer
C. Harmonic filter
Explanation
A harmonic filter is used to reduce voltage waveform distortion caused by harmonics. Harmonics are unwanted frequencies that can distort the shape of the voltage waveform, leading to issues such as overheating of equipment, interference with communication systems, and reduced power quality. A harmonic filter is designed to eliminate or reduce these harmonics, ensuring a cleaner and more stable voltage waveform. This helps to improve the overall efficiency and reliability of the electrical system.
8.
A lower K rating is better.
Correct Answer
B. False
Explanation
Higher K ratings are better
9.
What type of transformer has no electrical connection between the primary and secondary.
Correct Answer
C. Isolation transformer
Explanation
An isolation transformer is a type of transformer that has no electrical connection between the primary and secondary windings. It is designed to provide electrical isolation between the input and output, thereby preventing the transfer of electrical noise or voltage spikes from one circuit to another. This makes it useful in applications where safety or signal integrity is important, such as in medical equipment or audio systems.
10.
What generally causes harmonics
Correct Answer
C. Solid state devices
Explanation
Solid state devices, such as transistors and diodes, can generate harmonics in electrical systems. This is because these devices switch on and off rapidly, creating sudden changes in current flow. These rapid changes in current can produce high-frequency harmonics, which are multiples of the fundamental frequency. Harmonics can cause issues in power systems, such as overheating of equipment, interference with communication systems, and increased energy losses. Therefore, solid state devices are a common source of harmonics in electrical systems.
11.
The neutral conductor should be sized to carry ______ percent of the rated load
Correct Answer
D. 200%
Explanation
The neutral conductor should be sized to carry 200% of the rated load. This means that the neutral conductor should have a capacity twice the size of the rated load. This is necessary to ensure that the neutral conductor can handle any imbalances in the load and prevent overloading. By sizing the neutral conductor at 200% of the rated load, it provides a safety margin and helps maintain the balance of the electrical system.
12.
What tells the tranformers ability to dissipate heat.
Correct Answer
C. K-rating
Explanation
The K-rating of a transformer indicates its ability to dissipate heat. A higher K-rating means that the transformer is designed to handle higher levels of heat and can effectively dissipate it. This is important because transformers generate heat during operation, and if not properly dissipated, it can lead to overheating and damage to the transformer. Therefore, the K-rating is a crucial factor in determining the transformer's thermal performance and ensuring its safe and efficient operation.
13.
The ampacity of a conductor is related to the conductors:
Correct Answer(s)
A. Size
C. Temperature
D. Insulation
Explanation
The ampacity of a conductor refers to its ability to carry electrical current. The size of the conductor is an important factor in determining its ampacity, as larger conductors have more surface area for current to flow through. Temperature also affects the ampacity, as higher temperatures can cause the conductor to have a reduced carrying capacity. Additionally, the type and quality of insulation surrounding the conductor can impact its ampacity, as insulation helps to protect the conductor from overheating and potential damage. Therefore, the correct factors related to the ampacity of a conductor are size, temperature, and insulation.
14.
Conductor sizes larger than 4/0 are specified in terms of the total cross-sectional area of the copper measured in what:
Correct Answer
B. Circular mills
Explanation
Conductor sizes larger than 4/0 are specified in terms of the total cross-sectional area of the copper measured in circular mills. Circular mills is a unit of measurement commonly used in the electrical industry to express the size of large conductors. It represents the area of a circle with a diameter of one mil (1/1000th of an inch). This unit allows for a more precise measurement of conductor size, especially for larger conductors where millimeters or other units may not be practical.
15.
What is a unit of mechanical power
Correct Answer
D. Horsepower
Explanation
A unit of mechanical power is a measure of the rate at which work is done or energy is transferred in a mechanical system. The decibel (dB) is a unit used to measure the intensity of sound, not mechanical power. The watt (W) is the SI unit of power, but it is a general unit used for all types of power, not specifically mechanical power. The ohm (Ω) is a unit of electrical resistance, not power. Horsepower (hp) is a unit commonly used to measure mechanical power, especially in the context of engines and motors.
16.
One watt equals how many Btu.
Correct Answer
B. 3.413
Explanation
One watt is equal to 3.413 Btu. This conversion factor is used to convert between the units of power (watt) and energy (Btu). The Btu (British thermal unit) is a unit of energy commonly used in the United States, while the watt is the SI unit of power. Therefore, to convert from watt to Btu, we multiply the value in watt by 3.413.
17.
What type of circuit do you have if voltage leads current.
Correct Answer
C. Inductive
Explanation
If voltage leads current in a circuit, it means that the voltage waveform reaches its peak before the current waveform. This is a characteristic of an inductive circuit. Inductive circuits contain inductors, which store energy in a magnetic field. When the current changes, the magnetic field induces a voltage that opposes the change in current. As a result, the voltage leads the current in an inductive circuit.
18.
What type of circuit do you have is current leads voltage
Correct Answer
A. Capacative
Explanation
A capacitive circuit is one where the current leads the voltage. In a capacitive circuit, the current flow is ahead of the voltage waveform, meaning that the current reaches its peak before the voltage does. This is because in a capacitive circuit, the capacitor stores energy in an electric field and releases it back into the circuit, causing the current to lead the voltage.
19.
Inductive X is the portion of impedance that opposes a change in ________ flow due to magnetic field coupling
Correct Answer
C. Current
Explanation
Inductive impedance is the opposition to the change in current flow caused by the magnetic field coupling. As the magnetic field changes, it induces a voltage in the circuit, which in turn opposes the change in current flow. Therefore, the correct answer is current.
20.
Capacitive reactance (XC) is the portion of impedance that opposes a change in ______ due to electrical field coupling.
Correct Answer
A. Voltage
Explanation
Capacitive reactance (XC) is the portion of impedance that opposes a change in voltage due to electrical field coupling. In a capacitive circuit, the capacitive reactance increases as the frequency of the electrical signal increases. This means that as the voltage changes, the capacitive reactance opposes the change, resulting in a delay in the response of the circuit. Therefore, the correct answer is voltage.
21.
Load characteristics are:
Correct Answer
D. All of the above
Explanation
The load characteristics refer to the properties or behaviors exhibited by a load in an electrical circuit. Resistance is a measure of how much a load opposes the flow of current, inductance is the ability of a load to store energy in a magnetic field, and capacitance is the ability of a load to store energy in an electric field. Therefore, all of these options are correct as they represent different load characteristics.
22.
Delta is a method of connection for primary or secondary windings of a three-phase transformer bank in which the windings are connected in series to form a:
Correct Answer
D. Closed circuit
Explanation
The correct answer is closed circuit. In a delta connection, the primary or secondary windings of a three-phase transformer bank are connected in a closed circuit, forming a triangular shape. This configuration allows for a balanced load distribution and efficient power transmission.
23.
The most common three-phase services are:
Correct Answer(s)
A. 208 wye (Y)/120 volts
B. 240 volts
D. 480 Y/277 volts
Explanation
The most common three-phase services are 208 wye (Y)/120 volts, 240 volts, and 480 Y/277 volts. These voltage ratings are commonly used in commercial and industrial settings to power various equipment and machinery. The 208 wye (Y)/120 volts service is often used for smaller loads, while the 240 volts service is commonly found in residential and small commercial applications. The 480 Y/277 volts service is typically used for larger industrial loads. These voltage ratings allow for efficient and reliable distribution of electrical power in three-phase systems.
24.
The most common single-phase service is:
Correct Answer
A. 120/240 volts
Explanation
The most common single-phase service is 120/240 volts. This is because it is the standard voltage used in residential homes in many countries, including the United States. It provides a balance between sufficient power for household appliances and safety for everyday use. The 120 volts is used for lighting and smaller appliances, while the 240 volts is used for larger appliances such as air conditioners, ovens, and dryers.
25.
Wye is a method of connection that uses a:
Correct Answer
B. Common point
Explanation
The correct answer is "common point" because in a Wye connection, all three phases of the circuit are connected to a common point, known as the neutral point. This allows for the sharing of a common reference point for voltage and current measurements. It is commonly used in three-phase electrical systems to distribute power to various loads.
26.
The amplitude of a sine wave is expressed as either:
Correct Answer(s)
B. Voltage
D. Current
Explanation
The amplitude of a sine wave is a measure of its maximum displacement from the equilibrium position. It represents the maximum value of the waveform and is typically expressed in terms of voltage or current. In electrical circuits, voltage represents the potential difference between two points, while current represents the flow of electric charge. Therefore, it is appropriate to express the amplitude of a sine wave in terms of voltage or current. Resistance and power are not directly related to the amplitude of a sine wave.
27.
The rms value is __________ times the zero-to-peak value of the sine wave
Correct Answer
C. 0.7071
Explanation
The root mean square (rms) value of a sine wave is equal to 0.7071 times its zero-to-peak value. This is a known relationship in electrical engineering and is derived from the mathematical properties of sine waves. The rms value represents the effective value of the sine wave and is commonly used to calculate power or voltage in electrical systems.
28.
Electrical power provided to commercial buildings and residences is in the form of:
Correct Answer
B. AC
Explanation
The electrical power provided to commercial buildings and residences is in the form of AC (alternating current). AC is the most common form of electrical power used in these settings because it is more efficient for long-distance transmission and can easily be converted to different voltages. Unlike DC (direct current), which flows in only one direction, AC constantly changes direction, allowing for easier voltage regulation and reduced power loss. AC power is also compatible with most electrical devices and appliances used in commercial and residential settings.
29.
The authority having jurisdiction (AHJ) generally covers installations of communications equipment that is controlled exclusively by communications utilitites.
Correct Answer
B. False
Explanation
general does not cover
30.
To help identify conductors in the U.S. they are color coded. What color is typically assigned to 208Y/120 Phase C conductors:
Correct Answer
D. Blue
Explanation
In the U.S., conductors are color coded to help identify them. The color typically assigned to 208Y/120 Phase C conductors is blue.
31.
To help identify conductors in the U.S. they are color coded. What color is typically assigned to 208Y/120 Phase B conductors:
Correct Answer
A. Red
Explanation
In the U.S., conductors are color coded to help identify them. The color typically assigned to 208Y/120 Phase B conductors is red.
32.
To help identify conductors in the U.S. they are color coded. What color is typically assigned to 208Y/120 Phase A conductors:
Correct Answer
B. Black
Explanation
In the U.S., the color coding system is used to identify conductors. The color typically assigned to 208Y/120 Phase A conductors is black. This means that when you see a black conductor, you can expect it to be a Phase A conductor with a voltage of 208Y/120.
33.
For DC power system alarms, what are the two types of remote alarms:
Correct Answer(s)
A. Cabled remote
C. Dial-up remote
Explanation
The correct answer for this question is Cabled remote and Dial-up remote. These are the two types of remote alarms for DC power systems. A cabled remote alarm refers to an alarm system that is connected to the main system through cables. It allows for a direct and physical connection between the alarm and the main system. On the other hand, a dial-up remote alarm refers to an alarm system that uses a dial-up connection to communicate with the main system. It allows for remote monitoring and control of the alarm system through a telephone line.
34.
For Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair, what are the three main factors to consider for distance limitations:
Correct Answer
D. All of the above
Explanation
The three main factors to consider for distance limitations in ISDN power distribution over balanced twisted pair are the allowable voltage drop between the power source and the terminal, the size (wire gauge) of the pair, and the amount of power required by the terminal. All of these factors play a crucial role in determining the maximum distance over which power can be distributed effectively.
35.
For Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair, Which power method is suitable for residential and other low-quantity terminal users.
Correct Answer
C. Local or desktop power
Explanation
Local or desktop power is suitable for residential and other low-quantity terminal users when it comes to power distribution over balanced twisted pair in Integrated Services Digital Network (ISDN). This method involves providing power directly from a local or desktop power source to the terminal device, which is convenient and efficient for individual users. It eliminates the need for bulk power distribution, which is more suitable for larger scale deployments. Distributed power may also not be necessary for low-quantity terminal users as it involves distributing power from a centralized source to multiple devices, which may not be required in this scenario.
36.
For Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair, Which power method is most suitable for a single-building situation or whre there is an existing dc power plant.
Correct Answer
A. Bulk power
Explanation
Bulk power is the most suitable power method for a single-building situation or where there is an existing DC power plant. Bulk power refers to the centralized distribution of power from a main power source to multiple devices or locations. In this case, it would involve distributing power from the existing DC power plant to the various devices and equipment within the single building. This method allows for efficient power distribution and management, as well as easier maintenance and troubleshooting.
37.
For Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair, Which power method is most suitable for a campus-type installation or where there is a concentration of terminals to be powered in certain locations
Correct Answer
B. Distributed power method
Explanation
The distributed power method is most suitable for a campus-type installation or where there is a concentration of terminals to be powered in certain locations. This method involves distributing power from a central power source to multiple locations, allowing for efficient power distribution and reducing the need for long power cables. It is particularly beneficial in situations where there are multiple terminals in close proximity to each other, as it eliminates the need for individual power sources at each terminal.
38.
For Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair, what are three power methods:
Correct Answer
D. All of the above
Explanation
The correct answer is "All of the above". This means that all three power methods - bulk power, distributed power, and local or desktop power - are used for Integrated Services Digital Network (ISDN) power distribution over balanced twisted pair. This indicates that ISDN can be powered using any of these methods depending on the specific requirements and circumstances.
39.
If a flooded cell battery is used, the location should have:
Correct Answer
C. An eye wash facility
Explanation
The presence of an eye wash facility is necessary in a location where a flooded cell battery is used because flooded cell batteries contain corrosive chemicals that can cause harm if they come into contact with the eyes. An eye wash facility provides immediate access to water for rinsing the eyes in case of any accidental exposure or injury. This helps to minimize the potential damage and provide quick relief to the affected person.
40.
The optimum temperature that a battery should be maintained at is typically:
Correct Answer
C. 25 degrees C (77 degrees F)
Explanation
The optimum temperature for a battery is typically 25 degrees C (77 degrees F). This temperature provides the best balance between performance and longevity for the battery. Operating a battery at higher temperatures can cause it to degrade faster and reduce its overall lifespan. On the other hand, operating a battery at lower temperatures can decrease its performance and efficiency. Therefore, maintaining a battery at 25 degrees C (77 degrees F) is considered the ideal temperature for its optimal functioning.
41.
When designing the layout of a battery room you should avoid:
Correct Answer(s)
B. Exposing the battery plant to direct sunlight
D. Placing the battery adjacent to heating or cooling sources
Explanation
Exposing the battery plant to direct sunlight can cause the batteries to overheat and potentially explode. Placing the battery adjacent to heating or cooling sources can also cause temperature fluctuations that can negatively affect the battery's performance and lifespan. Therefore, it is important to avoid both of these situations when designing the layout of a battery room.
42.
When connecting batteries in parallel the maximum number of cells that can be connected are:
Correct Answer
C. 5
Explanation
When connecting batteries in parallel, the maximum number of cells that can be connected is 5. This means that you can connect up to 5 batteries together in a parallel circuit. Connecting more than 5 batteries in parallel can lead to issues such as unequal charging and discharging rates, which can reduce the overall performance and lifespan of the batteries. Therefore, 5 is the correct answer.
43.
A room that contains charging batteries must be vented to the outside atmosphere. A minimum of ____ changes of room air volume per hour is recommended.
Correct Answer
B. 4
Explanation
A room that contains charging batteries must be vented to the outside atmosphere to prevent the buildup of potentially harmful gases. A minimum of 4 changes of room air volume per hour is recommended to ensure proper ventilation and maintain a safe environment. This frequent exchange of air helps to remove any gases or fumes emitted by the charging batteries and maintain a fresh and clean atmosphere in the room.
44.
Because the lead in a lead-acid battery is soft, a hardening agent is usually added to the lead, what type of hardening agents are mainly used
Correct Answer(s)
A. Calcium
D. Antimony
Explanation
The correct answer is Calcium and Antimony. In a lead-acid battery, the lead is soft and therefore a hardening agent is added to improve its strength and durability. Calcium and Antimony are the main hardening agents used in lead-acid batteries. Calcium helps to improve the mechanical strength of the lead, while Antimony improves the battery's performance and prevents self-discharge.
45.
What is the most common type of alkaline cell:
Correct Answer
C. NiCd cell
Explanation
NiCd cell refers to Nickel-Cadmium cell, which is the most common type of alkaline cell. This type of cell uses nickel oxide hydroxide and metallic cadmium as electrodes, along with potassium hydroxide as the electrolyte. NiCd cells are known for their high energy density, long cycle life, and ability to provide a consistent voltage output. They are commonly used in portable electronic devices, such as cameras, cordless phones, and power tools.
46.
How can cells be connected to increase battery capacity.
Correct Answer
B. In parallel
Explanation
Connecting cells in parallel increases battery capacity by maintaining the same voltage while increasing the total current capacity. In parallel connection, the positive terminals of all cells are connected together, and the negative terminals are connected together. This allows the cells to share the load, resulting in a higher total current capacity. As a result, the battery can deliver more power and last longer.
47.
The capacity of a cell depends on what two factors
Correct Answer(s)
A. Size of the cell plates
C. Quantity of cell plates
Explanation
The capacity of a cell depends on the size and quantity of its cell plates. The size of the cell plates determines the surface area available for chemical reactions to occur, which affects the amount of charge the cell can hold. The quantity of cell plates also plays a role as more plates increase the overall surface area and hence the capacity of the cell. The charge time and type of cell plates are not mentioned as factors affecting the capacity of a cell.
48.
Batteries store energy in:
Correct Answer
C. Chemical form
Explanation
Batteries store energy in chemical form. When a battery is charged, a chemical reaction occurs that converts electrical energy into chemical potential energy. This energy is stored in the battery until it is needed. When the battery is connected to a device, a chemical reaction is again triggered, converting the stored chemical energy back into electrical energy, which powers the device. This chemical reaction is what allows batteries to store and release energy efficiently.
49.
What are the three main types of battery cells used in telecommunications applications:
Correct Answer(s)
A. Alkaline
B. Flooded lead-acid (FLA)
C. Valve regulated lead-acid (VRLA)
D. Wet cells
E. Sealed cells
Explanation
The three main types of battery cells used in telecommunications applications are alkaline, flooded lead-acid (FLA), and valve regulated lead-acid (VRLA). These types of batteries are commonly used in telecommunications due to their reliability and ability to provide a consistent power supply. Alkaline batteries are known for their long-lasting power and are often used in portable devices. Flooded lead-acid batteries are a traditional type of battery that requires regular maintenance and refilling of electrolyte fluid. VRLA batteries, on the other hand, are sealed and maintenance-free, making them a popular choice for telecommunications applications.
50.
Batteries store electricity.
Correct Answer
B. False
Explanation
Batteries do not actually store electricity, but rather they store chemical energy which is then converted into electrical energy when needed. When a battery is connected to a circuit, a chemical reaction occurs within the battery, causing a flow of electrons and generating an electric current. Therefore, it is incorrect to say that batteries store electricity directly.