Computer Hardware and Software Questions and Answers

Answer: B

Correct answer: It converts mains AC into the low-voltage DC the components need

The power supply unit converts the alternating current from the mains - 230 volts in India - into the low-voltage direct current the components require, chiefly +12 V, +5 V and +3.3 V, delivered through standard connectors. Its capacity is quoted in watts, and it must exceed the total draw of the components, with the graphics card and processor usually accounting for most of it. Efficiency is rated by the 80 Plus scheme, and a more efficient unit wastes less energy as heat. The second option describes an UPS, an uninterruptible power supply, which is a separate external device containing a battery. It provides enough time to save work and shut down cleanly, and also protects against surges and voltage fluctuation. The PSU is a common cause of intermittent faults that look like something else - random restarts and instability under load - because an inadequate or failing unit fails only when demand rises.

Answer: B

Correct answer: It is much faster because it has no moving parts

An SSD stores data in flash memory with no moving parts, so there is no seek time and no rotational delay. Random access in particular is faster by orders of magnitude, which is why replacing a hard disk with an SSD transforms the responsiveness of a computer more than almost any other upgrade. It is also silent, resistant to shock, lower in power consumption and cooler. The other options overstate the case. A hard disk still offers more capacity per rupee, which is why bulk storage and archives remain magnetic. And an SSD does wear: each flash cell tolerates a finite number of write cycles, which is why controllers use wear levelling to spread writes across the drive and over-provision spare cells. Modern drives outlast their usefulness in ordinary use, but the limit is real. Both require power to operate, and both retain data without it.

Answer: A

Correct answer: Access Point

A home network is built around an access point or wireless router, which joins the wired and wireless sides and provides addressing. A NIC belongs to one machine and FireWire is a peripheral bus.

Answer: A

Correct answer: 200

A person begins to feel a static discharge at around three thousand volts, so 200 V passes entirely unnoticed - while being several times what it takes to damage a chip.

Answer: C

Correct answer: The map statement is not in the autoexec.bat file

A mapping made at the command line lasts only for that session. To survive a restart it must be re-established at boot - from AUTOEXEC.BAT, or by ticking reconnect at logon.

Answer: B

Correct answer: A uniform negative charge is placed on the photosensitive drum

Conditioning is the first stage of the laser printing process: the primary corona lays an even negative charge over the whole drum, which the laser then selectively discharges to write the image.

Answer: D

Correct answer: characters per second

Dot matrix speed is quoted in characters per second, since the head prints one character at a time. Page printers are rated in pages per minute.

Answer: D

Correct answer: 2.5 - 5

Pin 1 of the AT supply carries Power Good, and the board is held in reset until that line rises into the TTL high range. If it never does, the machine never starts.

Answer: B

Correct answer: malfunctioning pick-up rollers

The rollers pick one sheet from the stack, and as their rubber hardens and polishes with age they slip - feeding nothing, or several sheets at once. That is the commonest tray fault in any printer.

Answer: A

Correct answer: RAM

RAM is electronic and reached in nanoseconds; a hard disk must move a head and wait for the platter, which takes milliseconds. ROM is also electronic but slower than RAM in the systems these questions describe.