Technology Questions and Answers

Answer: A

ARP stands for Address Resolution Protocol.

It finds the hardware MAC address matching a known IP address on a local network, by broadcasting a request that the owner of that address answers. Without it a packet could not be delivered on the final hop.

Answer: C

PLC stands for programmable logic controller.

It is a ruggedised industrial computer that reads sensors and drives motors, valves and relays on a factory floor. It replaced banks of hard-wired relays, and its logic is usually written as a ladder diagram.

Answer: B

PDF stands for Portable Document Format.

Adobe created it in 1993 so that a document would appear identically on any system, embedding fonts and layout in the file itself. It became an open ISO standard in 2008.

Answer: C

SMPS stands for switch mode power supply.

It converts mains AC to the low DC voltages a computer needs by switching at tens of kilohertz rather than using a heavy mains transformer, which makes it far lighter and more efficient than a linear supply.

Answer: C

Computers within a limited distance, connected to each other, form a local area network.

A LAN covers a building or campus and is owned by one organisation. A WAN spans a much greater distance and usually uses leased lines or public networks between its sites.

Answer: D

IPv4 addresses are 32 bits long.

They are written as four decimal numbers, each a byte, as in 192.168.1.1. That gives about 4.3 billion addresses, which ran out; IPv6 uses 128 bits and effectively cannot.

Answer: B

A JPG is a format for an image file.

JPEG compresses photographs by discarding the fine detail the eye notices least, achieving ten- or twentyfold reduction. Because the loss is cumulative, an image should be edited in a lossless format and saved as JPEG only at the end.

Answer: A

DPI stands for dots per inch.

It measures the resolution of a printer or scanner. 300 dpi is normal for documents and 600 or more for photographic printing; screen resolution is measured in pixels per inch instead.

Answer: D

All of these are electronic payment systems: credit cards, digital wallets and electronic cheques.

Card payment is much the largest by value; digital wallets store credentials for quick payment; and electronic cheques carry an instruction to debit an account, with a digital signature in place of a written one.

Answer: D

A .JPG file is an image file.

JPEG, the Joint Photographic Experts Group format, compresses photographs by discarding detail the eye is least sensitive to. The compression is lossy, so quality falls a little each time a file is re-saved.