Besides protecting a computer from under-voltages, a typical ups also performs which other actions?

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You are troubleshooting a client connectivity problem on an Ethernet network. The client system has intermittent connectivity to the network. You discover that the unshielded twisted-pair patch cable runs 75 ft from the wall outlet, passes through the ceiling and over several florescent light fixtures before reaching the client system. Which of the following may be a cause of the connectivity problem? A. Crosstalk B. The UTP cable does not support transmission distances of 75 feet without signal regeneration. C. Failed patch cable D. Attenuation E. EMI Interference	E. EMI Interference Explanation: In this case, the most likely cause of the problem is EMI from the florescent lights. Cables run near air conditioners, lights or other large electronic devices can create interference for data traveling through the cables. UTP cables in an Ethernet network have a maximum segment length of 100 ft. Distances beyond this length may require signal regeneration. Devices such as Ethernet switches provide signal regeneration. Attenuation describes the process of signal degradation as it passes through network media. As mentioned, UTP cables in an Ethernet network can run 100 feet before attenuation becomes a significant problem. Crosstalk refers to the interference caused by overlapping signals when cables are run in close proximity to each other.
Your organization uses an 802.11g wireless network. Recently, other tenants installed the following equipment in your building: A. A wireless television distribution system running at 2.4 GHz B. A wireless phone system running at 5.8 GHz C. A wireless phone system running at 900 MHz D. An 802.11a wireless network running in the 5.725-5.850 GHz frequency range. E. An 802.11n wireless network running in the 5.8 GHz frequency range. Since this equipment was installed, your wireless network has been experiencing significant interference. Which system is to blame?	A. The wireless TV system. Explanation: Because the 802.11g standard operates within the 2.4 GHz to 2.4835 GHz radio frequency range, the most likely culprit is the wireless TV distribution system.
What is the best way to protect a computer from power spikes during an electrical storm? A. Use a UPS. B. Unplug the computer from the AC outlet. C. Shut down the computer. D. Use a surge protector.	B. Unplug the computer from the AC outlet. Explanation: The best way to protect a computer from power spikes during an electrical storm is to unplug the computer from the AC outlet. Surge protectors and UPS units can help protect a computer from temporary, above-normal voltages. However, the only way to completely protect the computer is to disconnect the computer from the AC outlet.
What does a beeping from the UPS mean? A. The UPS battery is no longer able to hold a charge. B. The computer is running on the UPS battery power. C. The computer is about to shut down. D. The UPS is not connected to the computer. E. The power reserve in the UPS battery is critically low.	B. The computer is running on the UPS battery power. Explanation: A beeping from the UPS means the AC power is out and the computer is running on the UPS battery power. Most UPS’s will sound a warning signal when running on battery power. A failed connection between the UPS and the computer or a low battery on the UPS would most likely provide a visual notification on the computer screen from the UPS monitoring software, not an audible beep.
Besides protecting a computer from under voltages, a typical UPS also performs which other actions? (Select two) A. Prevents electric shock B. Protects from over voltages C. Conditions the power signal D. Protects network cabling from EMI E. Prevents ESD	B. and C. Protects from over voltages and conditions the power signal. Explanation: A typical UPS protects a computer from over voltages as well as under voltages. Also, because of the quality of the electrical signal provided by a UPS battery is not as good as the AC power from the wall outlet, UPS devices often have built-in line conditioners.
Which of the following are common tools used to physically clean the inside of a computer? (Select two) A. Natural bristle brush B. Industrial degreaser C. Damp rag D. Compressed air E. Wire brush	A. and D. Natural bristle brush and compressed air Explanation: You can use a natural bristle brush and can of compressed air to blow dust off of a motherboard and other circuit cards. Never use anything harsh such as a wire brush. Rags are also discouraged because they easily snap on electrical leads and parts. No liquids should ever be used to clean computer components.
You have ordered a new laptop from an online retailer. When you come home one day after work, you find the laptop in its shipping container on your front doorstep. It is very cold outside and you don’t know how long it has been there. You unpack the computer and would like to know if it is working properly. What should you do? A. Let the computer warm up to room temperature before turning it on. B. Place the laptop next to a heater set on High to warm it up. C. Visually inspect the LCD screen for cracks before turning it on. D. Turn on the computer and run self-diagnostic tests. E. Remove the back cover and blow out the inside with compressed air before turning it on.	A. Let the computer warm up to room temperature before turning it on. Explanation: If a computer has been in a cold environment, you should let it warm up to room temperature before turning it on. Otherwise the heat produced by the components might cause water condensation inside the computer. This water might then damage system components. However, placing the laptop next to a heater set on High would be a poor strategy for warming the system up because it could potentially melt the plastic parts within the unit.
Which of the following statements about cleaning monitors and display devices is true? A. An LCD monitor is best cleaned using a lint rag and glass cleaner. B. Monitors are best cleaned while powered on so that you will be able to observe the effectiveness of your cleaning. C. Most new monitors are self-cleaning and should not be cleaned using external methods. D. You should clean the monitor while it is powered off and with the power plug removed to avoid getting a shock.	D. You should clean the monitor while it is powered off and with the power plug removed to avoid getting a shock. Explanation: Some monitors, such as CRTs, can carry a strong electrical charge that may possibly dissipate when a conductor such as a cleaning solution is applied to the monitor screen. This can harm you as well as damage the monitor. Cleaning cloths should always be lint free, In general an LCD monitor is best cleaned using a dry cloth. While many newer monitors do have certain automatic calibration features, self-cleaning is not one of them.
You are trying to help a co-worker order a UPS for each PC in her remote office location. What rating is used to specify the size of a UPS? A. Watts B. VA C. Volt/ohm D. Volts	B. VA Explanation: The size of a UPS is specified by a volt-amp (VA) rating. The larger the VA rating 0f the UPS, the longer the UPS can keep the system running in the event of a power failure. Volts are only part of the rating system used for UPS units. Ohms are not used to rate UPS units nor is wattage.
Which of the following is most helpful in keeping a computer cool? (Select two.) A. Install a thermostat in the fan circuit. B. Vacuum dust from the system regularly. C. Verify that cooling fans are not circulating air in the wrong directions. D. Remove a slot cover from the back of the computer. E. Use a high-wattage power supply.	B. and C. Vacuum dust from the system regularly. Verify that cooling fans are not circulating air in the wrong directions. Explanation: Vacuuming dust from the system is critical for keeping the computer cool. In addition, verify that your cooling fans are blowing air the right direction and are not working against each other. Do not remove any slot covers in an attempt to cool the computer. A lack of slot covers decreases the fan’s ability to remove hot air from inside the computer.
Which of the following devices helps protect against temporary, above-normal voltages? A. ESD grounding strap B. Power strip C. Surge protector D. Grounding wire	C. Surge protector Explanation: A power surge is a temporary increase in excessive voltage to a computer. A surge protector helps protect against power surges. A power strip may or may not include surge protection circuits. An ESO grounding strap should be worn when touching anything inside a computer to avoid shocking computer components by not sharing a common ground.
Which of the following cleaning compounds should you include in your cleaning kit? A. Complementary metal oxide keyboard wipes B. Alcohol-based monitor wipes C. Chlorinated mouse wipes D. Ammonia-based toner wipes	B. Alcohol-based monitor wipes Explanation: Monitor wipes tor CRT/TV type monitors are usually alcohol-based. Be aware, however, that many LCD/LED monitor manufacturers recommend a clean, dry cloth to clean this type of monitor screen. Ammonia can react negatively to toner particles and should be avoided when cleaning near laser printers. Complementary metal oxide semi-conductor (CMOS) memory is used to store computer setup information and is not a cleaning product. Chlorinated wipes protect against germs and aren’t typically part of a computer cleaning kit.
Which of the following features should you look for when selecting a vacuum cleaner for your cleaning kit? (Select two) A. Coarse grade bag B. Static induction motor C. A vacuum cleaner that blows as well as vacuums D. Washable filters E. Non-static generating	C. and E. A vacuum cleaner that blows as well as vacuums and non-static generating Explanation: It is important to select a vacuum cleaner for use with computer equipment that will not generate harmful static. Electrostatic discharge should always be avoided around sensitlve computer components. In some cases it may be better to remove dust and other foreign matter by applying a blowing force rather than vacuuming. The bag used in this type of vacuum should be fine enough to collect toner particles. Otherwise these particles may circulate within and outside the vacuum and spread toner.
Which device type should typically not be plugged into a protected outlet on a UPS unit? A. External hard disk drive B. Inkjet printer C. Secondary monitor D. Laser printer	D. Laser printer Explanation: A laser printer should not be plugged into a UPS. Instead, a laser printer should be plugged directly into the wall. Typical UPS units are designed for personal computer power requirernents, and are not capable of handling the laser printer’s power requirements.