Which motor is NOT suitable for use as a DC machine?
Answer: C
The squirrel cage motor cannot be used as a DC machine.
It is an induction motor: it works only on alternating current, whose changing field induces current in the rotor bars. Permanent magnet, series and synchronous machines can all be built to run on direct current.
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Made from a variety of materials, such as carbon, which inhibits the flow of current...?
Answer: C
A component made of carbon or similar material to oppose the flow of current is a resistor.
Its value follows Ohm's law, \( V = IR \), and it dissipates the energy as heat. Chokes and inductors oppose changes in current rather than current itself, and capacitors block direct current entirely.
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'DTP' computer abbreviation usually means ?
Answer: B
DTP stands for desktop publishing.
It is the preparation of printed material on a personal computer, combining text, images and layout on screen. Aldus PageMaker on the Macintosh in 1985, with the LaserWriter, began it.
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'DB' computer abbreviation usually means ?
Answer: A
DB stands for database.
A database is an organised collection of data with software to store, retrieve and update it. The relational model, proposed by E.F. Codd in 1970, organises it into tables of rows and columns queried with SQL.
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What is part of a database that holds only one type of information?
Answer: B
The part of a database holding one type of information is a field.
A field is a column - surname, or date of birth. A record is a row, one complete entry made of all its fields, and a file or table is the whole collection of records.
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In the UK, what type of installation requires a fireman's switch?
Answer: A
Neon lighting requires a fireman's switch in the UK.
Discharge signs run at several thousand volts, which would remain live and dangerous to firefighters even with the ordinary supply cut. The switch is mounted outside, in a conspicuous position, and isolates the installation.
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A given signal's second harmonic is twice the given signal's __________ frequency?
Answer: C
The second harmonic is twice the fundamental frequency.
Any periodic wave can be resolved into a fundamental and harmonics at integer multiples of it. The relative strength of those harmonics is what makes a violin and a flute sound different at the same pitch.
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What does EPROM stand for?
Answer: B
EPROM stands for erasable programmable read-only memory.
It is programmed electrically and erased by strong ultraviolet light through a quartz window in the package, which is why such chips carried a covering label.
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Which of the following is not a method of accessing the web?
Answer: C
The CPU is not a method of accessing the web.
It is the processor inside the computer. A modem, ISDN line or DSL connection is what carries the data between the computer and the internet service provider.
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Which of the following is not a valid domain name?
Answer: C
www.fr.yahoo is not a valid domain name.
A domain name must end in a top-level domain such as .com, .uk or .fr. Here 'yahoo' is in the position a top-level domain should occupy, and there is no such TLD.
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