When measuring AC (Alternating Current) with a multimeter, it is important to maintain the proper polarity.
Answer: B
Correct answer: False
Alternating current reverses direction many times a second, so it has no fixed polarity to observe. Polarity matters when measuring direct current, where reversing the leads reverses the sign of the reading.
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You have just installed a new internal PCI modem on you desktop. It will not dial out. what is the problem?
Answer: D
Correct answer: the phone line out of the wall is plugged into the phone port on the modem
A modem has two identical sockets: line for the wall and phone for a handset. Interchanging them is the classic mistake, and the modem then hears nothing when it tries to dial.
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What can you use to ensure power is not interrupted, resulting in corrupted data?
Answer: A
Correct answer: UPS
Only a UPS supplies power through an interruption; a surge protector deals with the opposite problem, and grounding with a third.
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Most PCs give a single beep on bootup to indicate they are ok hardware wise. You boot your PC and don't get a beep. What should you check first?
Answer: D
Correct answer: speaker
The beep is the BIOS's only way of reporting before the display works, and no beep at all may mean simply that the speaker is disconnected. Checking it first avoids condemning a working board.
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You must service the laser printer in your office. Which part of the printer shoud you avoid touching because it is hot?
Answer: A
Correct answer: fuser
The fuser melts the toner into the paper, so it runs at around 200°C and stays hot for some time after the printer is switched off. It is the one part that will burn the hand.
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Which of these has the largest storage capacity, typically?
Answer: C
Correct answer: Hard disk drive
A hard disk drive holds far more than any of the others - terabytes, where the optical and magnetic media listed hold gigabytes or megabytes. The capacities are worth knowing in order, since the comparison is a standard question. A floppy disk held 1.44 MB. A CD holds about 700 MB. A DVD holds 4.7 GB single-layer and 8.5 GB dual-layer. A Blu-ray disc holds 25 GB per layer. A hard disk today holds several terabytes. The optical discs differ chiefly in the wavelength of the laser used: a shorter wavelength focuses to a smaller spot, so more pits fit on the same surface. CD uses infrared at 780 nm, DVD red at 650 nm, and Blu-ray blue-violet at 405 nm - which is where its name comes from. Solid-state drives now rival hard disks in capacity while being far faster, and cloud storage is effectively unlimited but depends on a connection.
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If a computer's BIOS allows it, you can boot from a CD-ROM.
Answer: A
Correct answer: True
The El Torito extension lets the BIOS read a bootable image from a CD, which is how operating systems came to be installed without floppies. The BIOS must support it and the CD must be earlier in the boot order.
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A dialog box with a bomb appears on a Macintosh screen. What type of problem has occurred?
Answer: B
Correct answer: A software problem
The bomb dialog is the classic Macintosh system error, raised when a program does something the system cannot recover from. It reports a software failure; hardware faults are reported differently, by the startup chimes.
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"Parity" errors usually indicate bad memory.
Answer: A
Correct answer: True
The parity bit is checked on every memory read, and a mismatch means the data has changed since it was written. That is a memory fault, which is what a parity error reports.
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Which of these is an example of an optical storage device?
Answer: B
Correct answer: DVD
A DVD is optical storage: data is written as microscopic pits on a reflective layer and read by a laser detecting the change in reflection. CDs and Blu-ray discs work the same way. The three storage technologies are distinguished by how the data is held. Magnetic storage - hard disks, tape - uses the orientation of magnetic domains. Optical storage uses pits read by a laser. Solid-state storage - SSDs, USB flash drives, memory cards - traps charge in floating-gate transistors with no moving parts at all. Optical media have particular strengths: they are cheap to mass-produce by stamping, immune to magnetic fields, and reasonably durable. Their weaknesses are low capacity, slow access and the need for a drive, which is why they have largely disappeared from laptops. RAM is not storage in this sense at all but volatile working memory.
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