更新された2024年04月テストエンジン練習CDCP問題集と練習試験合格させます
問題集お試しセットCDCPテストエンジンで問題集トレーニングには73問あります
質問 # 30
Which type of copper wire is used for grounding the racks to the SRG?
- A. Thin copper cable to keep the cost low for grounding.
- B. Copper cable with plastic insulation (isolation).
- C. Braided copper wire or flat copper strip.
- D. Thick copper cable to create better grounding.
正解：C
解説：
The type of copper wire that is used for grounding the racks to the SRG (signal reference grid) in a data centre is braided copper wire or flat copper strip, according to the CDCP Preparation Guide1 and various web sources234. Braided copper wire or flat copper strip are preferred over thin or thick copper cable for grounding purposes, because they havelower impedance and higher surface area, which allow better dissipation of electrical noise and interference. Moreover, braided copper wire or flat copper strip are more flexible and durable than copper cable, which make them easier to install and maintain. Braided copper wire or flat copper strip should be connected to the SRG using exothermic welding or other code-compliant methods, and should follow the relevant standards and codes, such as ANSI/TIA/EIA-607 and NFPA 70.
References:
1: CDCP Preparation Guide, page 23, section 2.4.2 2: Signal Reference Grid | Enterprise Data Center Design and Methodology5, page 1, section 1 3: Grounding System Ground Rod Stacking Installation - Rain Bird6, page 1, section 1 4: SmartRack Copper Bus Grounding Bar - Eaton Website7, page 1, section 1
質問 # 31
What is the most preferred unit of measure for cooling capacity?
- A. Ton
- B. Watt
- C. BTU
- D. Horsepower
正解：B
解説：
Cooling capacity is the measure of a cooling system's ability to remove heat from a space. The most preferred unit of measure for cooling capacity is watt (W), which is the SI unit for power. Watt is defined as the amount of energy transferred or converted per unit time. One watt is equal to one joule of energy per second. Using watt as the unit of measure for cooling capacity allows for easy comparison and calculation of the cooling performance and efficiency of different cooling systems.
Other units of measure for cooling capacity are ton, BTU, and horsepower, but they are less common and less convenient than watt. Ton is a unit of measure that describes how much water at freezing temperature can be frozen in 24 hours, equivalent to 3.5 kW or 12,000 BTU/h. BTU (British Thermal Unit) is a unit of measure that describes the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit, equivalent to 0.293 W. Horsepower is a unit of measure that describes the rate at which work is done, equivalent to 746 W.
References:
*Data Centre Professional (CDCP®) Reference Materials, page 8, section 2.1.1
*Data Centre Professional (CDCP®) Preparation Guide, page 11, section 2.1.1
*Cooling capacity - Wikipedia
*Air Conditioner BTU Calculator
*Air conditioning 101: Basics, working principle and sizing ... - GlobalSpec
*How is cooling capacity measured? - Sage-Advices
*Everything You Need to Know About Cooling Capacity
質問 # 32
What is the main risk for a data centre when the water supply fails?
- A. Failure to the water supply could result in sudden changes of the relative humidity in the Computer room.
- B. Failure to the water supply could result in DX cooling systems to fail.
- C. Failure to the water supply could result in IT failure and/or denial of access to operate.
- D. Failure to the water supply could cause issues for the cooling of back-up generators.
正解：D
解説：
Back-up generators are essential for providing power to the data centre in case of a utility outage. However, back-up generators also generate a lot of heat, which needs to be dissipated by a cooling system. The cooling system may rely on water supply, either from the municipal network or from a dedicated tank. If the water supply fails, the cooling system may not function properly, leading to overheating and potential damage to the generators. This could compromise the reliability and availability of the data centre power supply and cause downtime or data loss.
References:
1: CDCP Preparation Guide, page 18, section 2.3.2 2: Data Center Generator Cooling Systems3, page 1, section 1 4: Data Center Cooling Systems5, page 1, section 1
質問 # 33
The UPS vendor is offering the latest model of their UPS to you. The vendor indicates that the UPS is categorized as VFD class.
Is this UPS a fit for your mission-critical data centre?
- A. Yes
- B. Yes, but only if you oversize the battery bank with 10%.
- C. No
- D. Yes, but only if they install it with a 12-pulse rectifier.
正解：C
解説：
A UPS (uninterruptible power supply) that is categorized as VFD class is not a fit for your mission-critical data centre, because it does not provide adequate protection against voltage and frequency variations. VFD stands for Voltage and Frequency Dependent, which means that the output voltage and frequency of the UPS depend on the input voltage and frequency. VFD UPSs are also known as offline, standby, or line-interactive UPSs. They typically switch to battery power only when the input power fails or goes beyond a certain threshold. However, this switching may cause a brief interruption or a transient in the output power, which can affect the performance and reliability of the ICT equipment. Moreover, VFD UPSs do not filter or regulate the input power, which means that they pass on any voltage or frequency fluctuations, harmonics, or noise to the output power. These power quality issues can also damage or degrade the ICT equipment and the data.
For your mission-critical data centre, you need a UPS that is categorized as VFI class, which stands for Voltage and Frequency Independent. VFI UPSs are also known as online, continuous, or double-conversion UPSs. They provide a constant and clean output power that is independent of the input power. VFI UPSs convert the input AC power to DC power, and then convert it back to AC power with the desired voltage and frequency. This double conversion process isolates the output power from the input power, and eliminates any power quality issues. VFI UPSs also have zero switching time, which means that they do not cause any interruption or transient in the output power when switching to battery power. VFI UPSs are designed to protect the ICT equipment and the data from any adverse effects of voltage and frequency variations, and to ensure the highest level of availability and reliability.
References:
1: CDCP Preparation Guide, page 17, section 2.3.1 2: Understanding UPS Classification: Fuji Electric's Technical Guide3, page 1, section 1 4: Uninterruptible Power Supplies Key Product Criteria5, page 1, section
1 6: UPS Function: Reduced Input Voltage for VFDs - KEB7, page 1, section 1
質問 # 34
Which one of the following does a Physical Infrastructure consists of in a Data Centre?
- A. Switch
- B. Rack
- C. Hub
- D. Server
正解：B
解説：
A physical infrastructure in a Data Center consists of racks, which are metal frames used to store and organize server and other IT equipment. The racks are usually arranged in rows and columns, and they can be used to hold servers, storage devices, and other pieces of IT equipment. The racks can also be used to organize cables and other components to ensure that the Data Center is kept organized and efficient.
質問 # 35
What should be a consideration when having casters (rollers/wheels) or feet under the rack?
- A. The casters and feet should be larger to avoid a too heavy point load on the floor tile.
- B. Casters and feet should not be locked to ensure the racks are still able to be moved to another position.
- C. Casters and feet should be of a soft material, for example rubber, to avoid damage to the raised floor tile.
- D. Skirts at the bottom of the rack to avoid air flow between the hot and cold aisles.
正解：A
解説：
The casters and feet under the rack are used to support the weight of the rack and its equipment, and to allow the rack to be moved if needed. However, the casters and feet should also be designed to avoid putting too much pressure on the floor tile, especially if the data centre uses a raised floor system. A too heavy point load on the floor tile can cause the tile to crack, deform, or collapse, which can damage the rack, the equipment, and the underlying infrastructure. To prevent this, the casters and feet should be larger, so that they can distribute the weight over a larger area and reduce the point load. The casters and feet should also be compatible with the floor type and the load rating of the floor tile.
References:
1: CDCP Preparation Guide, page 22, section 2.4.1.1 2: Raised Floor Design Considerations for Data Center3, page 1, section 1 4: [SOLVED] server rack on casters or feet5, page 1, section 1
質問 # 36
When having two non-synchronized power sources, the ATS / STS need to be of the type:
- A. Both make before break or break before make can be used.
- B. Break before make.
- C. Both an ATS and STS can never handle two non-synchronized sources.
- D. Make before break.
正解：B
解説：
When having two non-synchronized power sources, the ATS / STS need to be of the type break before make, which means that the switch disconnects from one source before connecting to the other source. This prevents any short circuit, back feed, or phase mismatch that could occur if the two sources were connected simultaneously. Break before make switches are also known as open transition switches, because they create a brief interruption in the power supply during the switching process. This interruption is usually acceptable for most ICT equipment, as they have internal power supplies or batteries that can handle the transient. However, if the interruption is not acceptable, then the two power sources need to be synchronized before switching, which requires a make before break switch, also known as a closed transition switch. Make before break switches connect to the second source before disconnecting from the first source, which ensures a seamless transfer of power without any interruption. However, make before break switches require that the two sources have the same voltage, frequency, and phase, which can be achieved by using a synchronization module or a phase-locked loop.
References:
1: CDCP Preparation Guide, page 17, section 2.3.1 2: STS in data centres - Borri3, page 1, section 1 4: Using Static Transfer Switches to Enhance Data Center ... - Donwil5, page 1, section 1 6: What is an Automatic Transfer Switch (Power)? | Ethan Banks7, page 1, section 1
質問 # 37
Which type of Humidifier rapidly vibrates waster to create a fog or mist?
- A. Water Canister Humidifier
- B. Ultrasonic Humidifier
- C. Infrared Humidifier
- D. Steam Canister Humidifier
正解：B
解説：
An ultrasonic humidifier is a type of cool mist humidifier that uses a metallic diaphragm that vibrates at high frequencies to create water droplets that are added to the air. A fan projects these droplets into the air as mist, which then evaporates and humidifies the room. This type of humidifier rapidly vibrates the water to create a fog or mist.
References: EPI Data Centre Training Framework, How Humidifiers Can Help Allergies, Humidifier Buying Guide: Pros and Cons of Different Types.
質問 # 38
The three elements of the fire triangle are,and. (Choose three.)
- A. Heat
- B. Water
- C. Fuel
- D. Oxygen
- E. Earth
正解：A、C、D
解説：
The fire triangle is a simple model that illustrates the three elements that a fire needs to ignite and sustain:
oxygen, heat, and fuel. Oxygen is the oxidizing agent that enables the combustion reaction, heat is the energy source that raises the temperature of the fuel to its ignition point, and fuel is the material that reacts with oxygen and releases heat and light. Removing any one of these elements can extinguish a fire. For example, water can reduce the heat and the oxygen, sand or soil can smother the fuel and the oxygen, and fire extinguishers can displace the oxygen or lower the temperature.
References: EPI Data Centre Professional (CDCP®) Reference Materials, page 66.EPI Data Centre Framework, Module 4: Fire Protection, page 4. 1, 2, 3.
質問 # 39
is the degree to which a system or component is operational and accessibility when required for use.
- A. Agility
- B. Scalability
- C. Availability
- D. Reliability
正解：C
解説：
Availability is the degree to which a system, product or component is operational and accessible when required for use. It is one of the attributes of reliability, which is the ability of a system or component to perform its required functions under stated conditions for a specified period of time. Availability can be calculated as the ratio of the expected value of the uptime (the time when the system is functional) to the total time (uptime plus downtime) of a system or component. Availability can also be influenced by factors such as maintainability, fault tolerance, redundancy, diagnostics, and logistics.
References: EPI Data Centre Professional (CDCP®) Preparation Guide, page 8; Availability - Wikipedia; Reliability - ISO 25000.
質問 # 40
is the arithmetic mean of time between the failing and the subsequent running of the system in a particular time period.
- A. MCBF
- B. MTBF
- C. MLBF
- D. MTTR
正解：B
解説：
MTBF stands for Mean Time Between Failures, and it is the arithmetic mean of time between the failing and the subsequent running of the system in a particular time period. MTBF is a measure of reliability that indicates how often a system or component fails during its operation. MTBF can be calculated by dividing the total operating time by the number of failures over a given period. For example, if a system operates for 1000 hours and experiences 5 failures, the MTBF is 1000/5 = 200 hours.
References: EPI Data Centre Training Framework, CDCP Preparation Guide, MTBF, MTTR, MTTF, MTTA:
Understanding incident metrics - Atlassian
質問 # 41
Which one of the following is used in Measuring Business Value?
- A. Regeneration Cost
- B. Upfront Cost
- C. Scalability
- D. Reliability
正解：C
解説：
Measuring business value is the process of assessing the benefits and costs of IT investments and initiatives in relation to the strategic objectives and priorities of the organization. One of the factors that can be used to measure business value is scalability, which is the ability of a system or component to handle increasing workloads or demands without compromising performance, quality, or functionality. Scalability is important for business value because it enables the organization to adapt to changing market conditions, customer expectations, and growth opportunities. Scalability can also reduce operational costs, increase efficiency, and improve customer satisfaction. Therefore, scalability is one of the factors that can be used in measuring business value.
References:
*EPI Data Centre Training Framework1
*EPI Data Centre Competence Framework2
*Measuring the Business Value of IT3
*How to Measure the Business Value with Effective Data Quality Governance
*7 Rules for Demonstrating the Business Value of IT
質問 # 42
Sprinkler heads used in computer rooms activate at what temperature?
- A. 27 °C (81 °F)
- B. Only on direct contact with a flame
- C. 57 °C (135 °F)
- D. 70 C (158 °F)
正解：C
解説：
Sprinkler heads used in computer rooms activate at 57 °C (135 °F), which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler. Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.
References:
1: CDCP Preparation Guide, page 24, section 2.4.3 2: Sprinkler Systems in Data Centers3, page 1, section 1 4:
Data Center Fire Protection5, page 1, section 2 6: Data Center Sprinkler System Design7, page 1, section 1
質問 # 43
Which Class of Fires involves cooking appliances?
- A. Class K
- B. Class A
- C. Class B
- D. Class C
正解：A
解説：
According to the EPI Data Centre Professional (CDCP®) Preparation Guide, Class K fires involve cooking appliances that use combustible cooking media such as vegetable or animal oils and fats (page 28). Class K fires require special extinguishing agents that can suppress the high-temperature flames and prevent re-ignition. Class K fires are different from Class B fires, which involve flammable liquids such as gasoline, oil, or paint.
References:
*EPI Data Centre Professional (CDCP®) Preparation Guide, page 28
*Fire Classes and Extinguishing Agents | The Fire Equipment Manufacturers' Association
質問 # 44
An optical fiber cable comes with the specifications 50/125 um.
What do the numbers represent?
- A. The first number represents the required distance to single-phase power cabling; the second number represents the required distance to three-phase cabling.
- B. The first number represents the distance for a 10 Gb/s connection; the second number represents the distance for a 1 Gb/s connection.
- C. The first number represents the diameter of the core; the second number represents the diameter of the cladding in microns.
- D. The first number represents the diameter of the core; the second number represents the actual diameter cable including the buffer and jacket.
正解：C
解説：
Optical fiber cables are composed of a core, a cladding, and a coating. The core is the central part of the fiber that carries the light signal. The cladding is the layer surrounding the core that reflects the light back into the core and prevents signal loss. The coating is the protective layer that covers the cladding and provides mechanical strength and environmental protection. The specifications of an optical fiber cable indicate the dimensions of the core and the cladding in microns (m), which are one millionth of a meter. For example, a
50/125 m cable has a core diameter of 50 m and a cladding diameter of 125 m. The coating diameter is usually
250 m, but it is not part of the specifications.
References: Multimode Optical Fiber Selection & Specification - Corning, Optical Fiber OM3 (50/125µm Multimode Fiber), 50/125 Graded-Index OM2 Optical Fiber - OFS
質問 # 45
By what are magnetic fields of the type 'H' or 'B' created?
- A. Magnetic fields are created by the magnetic flux of the earth which varies per month.
- B. Magnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.
- C. Magnetic fields are created when there is a high level of common mode noise (CMN); the greater the common mode noise (CMN), the stronger the magnetic field.
- D. Magnetic fields are created by voltage; the greater the voltage, the stronger the magnetic field.
正解：B
解説：
According to the CDCP Preparation Guide1, magnetic fields of the type 'H' or 'B' are created when an electric current flows through a conductor, such as a wire or a coil. The magnetic field strength 'H' is proportional to the current 'I' and the number of turns 'N' of the coil, and inversely proportional to the length
'l' of the coil. The magnetic flux density 'B' is proportional to the magnetic field strength 'H' and the permeability '' of the medium in which the magnetic field exists. The greater the current, the stronger the magnetic field and the magnetic flux density. The relationship between 'H', 'B', 'I', 'N', 'l', and '' can be expressed by the following equations:
H = N I / l
B =H
References:
1: CDCP Preparation Guide, page 23, section 2.4.2.1 2: Difference between B and H in magnetic fields?3, page 1, section 1 4: Magnetic field | Definition & Facts5, page 1, section 1
質問 # 46
Which type of Fire Detection Device is recommended for protecting a Data Center?
- A. Smoke detector
- B. Flame detector
- C. None of the above
- D. Heat detector
正解：A
解説：
According to the CDCP® Preparation Guide, smoke detectors are the most common type of fire detection devices used in data centers, as they can detect a fire in its early stages and provide early warning to the occupants and authorities. Smoke detectors can be either spot-type or air-aspirating, depending on the design and goals of the data center. Spot-type detectors are inexpensive and simple, but may cause activation delay and false alarms. Air-aspirating detectors are more sensitive and reliable, but may require more maintenance and installation costs. Both types of detectors should be installed in accordance with the relevant standards and codes, such as NFPA 72 and EN 54.
References: CDCP® Preparation Guide, page 30-31. Evaluating Fire Detection Options For Data Centers. Fire Detection and Suppression Systems in a Data Center.
質問 # 47
Which one of the following is the last stage in Stages of Combustion?
- A. Incipient
- B. Flaming Fire
- C. Intense Heat
- D. Visible Smoke
正解：B
解説：
The last stage in stages of combustion is flaming fire, which occurs when the fuel vapors and oxygen are mixed in the right proportion and ignited by a flame or a spark. Flaming fire is characterized by visible flames, intense heat, and rapid oxidation. Flaming fire can cause severe damage to the data center equipment, personnel, and business continuity. Therefore, it is important to prevent or suppress flaming fire as soon as possible using appropriate fire detection and suppression systems.
References:
*EPI Data Centre Professional (CDCP®) Preparation Guide, page 31
*[Fire Detection and Suppression Systems for Data Centers]
質問 # 48
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