Whereas a computer mouse moves over the table surface, the trackball is
Answer: A
Correct answer: Stationary
A trackball is a mouse turned upside down: the ball is on top and the body stays still on the desk, the user rolling the ball with fingers or thumb. It needs no clear space to move in, which is why it was used on early laptops and is still used in confined spaces.
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Integrated circuits (ICs) are related to which generation of computers?
Answer: C
Correct answer: Third generation
Integrated circuits define the third generation (about 1964-71). The first generation used vacuum tubes, the second discrete transistors, and the fourth the microprocessor - which is itself an integrated circuit, but on the far larger scale of LSI and VLSI.
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What is the responsibility of the logical unit in the CPU of a computer?
Answer: B
Correct answer: To compare numbers
The logic half of the ALU performs comparisons - equal to, greater than, less than - and the results are what conditional branches act on. The arithmetic half does the calculation, and the control unit directs the flow of information.
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Which of the following IC was used in third generation of computers?
Answer: D
Correct answer: Both a and b
Third-generation machines used SSI (small-scale integration, tens of transistors per chip) and then MSI (medium-scale, hundreds). LSI and VLSI, with thousands and then millions, belong to the fourth generation and made the microprocessor possible.
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Abacus was the first
Answer: D
Correct answer: mechanical calculator
The abacus, some 5,000 years old, is a mechanical calculating aid: beads moved on rods represent the digits, and the operator performs the arithmetic. It stores no program and does nothing by itself, so it is a calculator rather than a computer - and certainly not electronic.
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The accuracy of the floating-point numbers representable in two 16-bit words of a computer is approximately
Answer: B
Correct answer: 6 digits
Two 16-bit words give 32 bits, of which the standard single-precision format uses 24 for the significand (23 stored plus one implied). Since
\[ 2^{24} \approx 1.7 \times 10^{7} \]that is worth about 7 decimal digits, of which 6 can be relied on. Doubling the storage to 64 bits raises it to roughly 15.
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The arranging of data in a logical sequence is called
Answer: A
Correct answer: Sorting
Sorting is arranging records into a defined order - alphabetical, numerical, by date. Classifying is grouping them by category, summarising is condensing them, and reproducing is copying.
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Each set of Napier’s bones consisted of ______ rods.
Answer: C
Correct answer: 11
A set of Napier’s bones comprised eleven rods - one index rod plus one for each digit, with the multiples of that digit engraved down its length. Laying the rods for the digits of a number side by side reduced multiplication to reading off partial products and adding them - and division to the same process in reverse. Napier described them in 1617.
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A technique used by codecs to convert an analogue signal into a digital bit stream is known as
Answer: A
Correct answer: Pulse code modulation
PCM converts an analogue signal to digital in three steps: sampling it at regular intervals, quantising each sample to the nearest of a set of levels, and encoding that level as a binary number. It is how speech becomes bits in digital telephony, and how sound is stored on a CD - 44,100 samples a second at 16 bits.
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A hybrid computer
Answer: C
Correct answer: Resembles both a digital and analogue computer
A hybrid computer combines the two: an analogue section measures continuously varying physical quantities, and a digital section computes and controls. Hospital intensive-care monitors are the standard example - analogue measurement of pulse and blood pressure, digital processing and display.
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