Computer & Information Technology

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Q20. In optical fibre transmission, LEDs and laser diodes serve as which components?

[RRB ALP, 23 January 2019, Shift 1]

1. Detectors
2. Light sources
3. Repeaters
4. Amplifiers

Answer: B. Light sources

Explanation: At the transmitting end of an optical fibre link, an LED or laser diode converts an electrical signal into modulated light. At the receiving end, a photodetector changes arriving light back into an electrical signal. Sources and detectors therefore play distinct roles.

Q19. What is the general name for instructions and programs that direct a computer’s operations?

[CG Vyapam Patwari 2019]

1. Hardware
2. Keyboard
3. Software
4. Mouse

Answer: C. Software

Explanation: Software consists of programs and related instructions that tell computing hardware what operations to perform. System software manages resources, while application software provides specific user functions. Keyboards and mice are tangible hardware rather than executable programs.

Q18. Which logical implication is a tautology?

[UPPSC LT Grade Assistant Teacher (Computer), 29 July 2018]

1. (a OR b) implies (b AND c)
2. (a AND b) implies (b OR c)
3. (a OR b) implies (b implies c)
4. None of these

Answer: B. (a AND b) implies (b OR c)

Explanation: Whenever a AND b is true, b is necessarily true, and therefore b OR c must also be true. When the antecedent is false, the implication is true by definition. Thus the second expression is true under every Boolean assignment.

Q17. Which mathematical system underpins binary logical operations in a computer?

[RPSC RAS Prelims 2018]

1. Abstract algebra
2. Matrix algebra
3. Boolean algebra
4. Linear algebra

Answer: C. Boolean algebra

Explanation: Boolean algebra works with logical values such as true and false, commonly represented by binary one and zero. Its operations AND, OR and NOT form the basis of digital logic. Processor circuits implement these operations using electronic gates.

Q16. A USB pen drive belongs to which broad storage category?

[WBCS Prelims 2018]

1. Primary storage
2. Secondary storage
3. Tertiary storage
4. None of these

Answer: B. Secondary storage

Explanation: A pen drive is nonvolatile removable secondary storage, typically using NAND flash memory. It retains documents even when unplugged. Primary memory such as RAM is used for active processing, while tertiary storage often describes large automated archival media systems.

Q15. In a traditional 16-bit word-size context, a sequence of 16 bits is called a ______.

[WBCS Prelims 2018]

1. Word
2. Nibble
3. Memory block
4. Byte

Answer: A. Word

Explanation: A word is a processor-dependent group of bits handled as a unit; sixteen bits constitute a word on a 16-bit architecture. A nibble contains four bits and a byte contains eight. Word size is not universally fixed across computers.

Q14. Where does a computer connect external accessories such as a printer or keyboard?

[MPPSC General Studies 2016]

1. Port
2. Ring
3. Bus
4. ZIP

Answer: A. Port

Explanation: A port is a physical or logical interface for exchanging information with connected devices. USB, HDMI and Ethernet sockets are familiar physical ports. A bus is a broader system of signal paths and does not specifically mean an external accessory socket.

Q13. Which portion of ‘http://www.google.co.in’ identifies the communication protocol?

[Rajasthan TRA Paper I, 2 August 2015]

1. .co
2. .in
3. www
4. http

Answer: D. http

Explanation: The scheme before the colon identifies the protocol or access method of a URL. Here ‘http’ means Hypertext Transfer Protocol. The ‘www’ part is a host label, while ‘.co.in’ contributes to the domain name structure.

Q12. Which statement about a modem is correct?

[RPSC RAS Prelims 2013]

1. It is software
2. It stabilises voltage
3. It is an operating system
4. It converts digital signals to analogue and back

Answer: D. It converts digital signals to analogue and back

Explanation: The name modem comes from modulator-demodulator. The hardware translates digital data to signals suitable for transmission over a communication medium and reverses the operation for incoming information. It does not replace the operating system or regulate supply voltage.

Q11. The names Celeron, Pentium and Core refer to which computer component family?

[RPSC RAS Prelims 2013]

1. RAM chips
2. Generic memory modules
3. Processors
4. All of the above

Answer: C. Processors

Explanation: Celeron, Pentium and Core are Intel processor brand families. A processor interprets and executes instructions and performs arithmetic and logical operations. RAM is separate working memory. Naming may change between product generations, but these labels historically refer to CPU ranges.