OPEN LEARNING LIBRARYASOC Question Bank
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194 matching questions
Question #1Radio Theory and Communication Principles
Parameter that determines lowest signal reception capability of a receiver is
- Sensitivity ✓ Correct answer
- Fidelity
- Selectivity
- Squelch
Explanation: Sensitivity is the ability to receive weak signals.
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Question #2Radio Theory and Communication Principles
TRF stands for
- Turning radio frequency
- Turning rod frequency
- Tuned radio feed
- Tuned radio frequency ✓ Correct answer
Explanation: TRF means Tuned Radio Frequency.
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Question #3Radio Theory and Communication Principles
If a super hetero dyne radio receiver is tuned to 1255 KHz & the IF frequency is 455KHz, then the frequency of the local oscillator of the receiver is
- 1255 KHz
- 800 KHz
- 1710 KHz ✓ Correct answer
- 455 KHz
Explanation: For a conventional high-side oscillator, LO = 1255 + 455 = 1710 kHz.
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Question #5Radio Theory and Communication Principles
Among all these materials, which one has poor conductivity ?
- Copper
- Aluminum
- Silicon ✓ Correct answer
- Silver
Explanation: Silicon is a semiconductor and conducts much less readily than the listed metals.
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Question #6Radio Theory and Communication Principles
A magnet does not attract which one in the following
- Nickel
- Aluminum ✓ Correct answer
- Iron
- Cobalt
Explanation: Aluminium is not ferromagnetic; nickel, iron and cobalt are attracted by a magnet.
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Question #8Radio Theory and Communication Principles
The expanded form for ‘LDR’ is
- Light Emitting Display
- Low Dependent Reading
- Light Emitting Diode
- Light Dependent Resistor ✓ Correct answer
Explanation: LDR means Light Dependent Resistor.
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Question #13Radio Theory and Communication Principles
The high frequency band (HF) is
- 3KHz to 30KHz
- 3MHz to 30MHz ✓ Correct answer
- 30KHz to 300KHz
- 30MHz to300MHz
Explanation: The HF band extends from 3 MHz to 30 MHz.
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Question #16Radio Theory and Communication Principles
If a small value of inductance is connected in parallel with a large value, the combined inductance will be
- The same
- Higher
- Lower ✓ Correct answer
- Cannot be determined with the given data.
Explanation: For inductors in parallel, the equivalent inductance is lower than the smaller inductance (for ideal uncoupled inductors).
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Question #22Radio Theory and Communication Principles
A domestic inverter
- Converts ac to ac
- Converts ac to dc
- Converts dc to ac ✓ Correct answer
- Converts dc to dc
Explanation: A domestic inverter converts DC from a battery into AC.
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Question #25Radio Theory and Communication Principles
The tolerance bands with colors gold, silver & brown represent
- 5%, 10%, 2%
- 5%, 10%, 1% ✓ Correct answer
- 10%, 5%, 1%
- 10%, 5%, 2%
Explanation: Gold, silver and brown tolerance bands represent 5%, 10% and 1%, respectively.
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Question #26Radio Theory and Communication Principles
India uses which encoding technique for commercial TV broad cast
- NTSC
- SECAM
- PAL ✓ Correct answer
- None of the above
Explanation: India’s analogue terrestrial television system used PAL.
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Question #27Radio Theory and Communication Principles
The video bandwidth in a TV transmission in India is
- 455 KHz
- 10.7 MHz
- 4.2 MHz ✓ Correct answer
- 5.5 MHz
Explanation: The conventional Indian PAL-B/G television system used approximately 5.5 MHz sound spacing and 5 MHz channel characteristics; the stated video bandwidth answer in this legacy question is 4.2 MHz.
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Question #33Radio Theory and Communication Principles
For mobile communications, the up-link frequency is _____ down link frequency .
- Less than
- More than ✓ Correct answer
- Equal to
- Less or more than the
Explanation: In typical cellular systems, the mobile uplink frequency is higher than the downlink frequency.
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Question #34Radio Theory and Communication Principles
All India Radio (AIR) does not broadcast
- Amplitude Modulation transmission
- Frequency Modulation transmission
- Pulse Modulation transmission ✓ Correct answer
- Both a and b
Explanation: Pulse modulation is not a normal broadcast mode used by All India Radio.
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Question #36Radio Theory and Communication Principles
Geo stationary orbit is ___ km away from the earth
- 3100
- 35,786 km ✓ Correct answer
- 36786
- 39000
Explanation: A geostationary orbit is approximately 35,786 km above the Earth’s equator.
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Question #41Radio Theory and Communication Principles
Digital modulation techniques are
- Amplitude modulation
- Frequency modulation
- Phase shift keying ✓ Correct answer
- Phase modulation
Explanation: Phase-shift keying (PSK) is a digital modulation technique.
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Question #42Radio Theory and Communication Principles
The following idle component dissipates energy
- Capacitor
- Inductor
- Resistor ✓ Correct answer
- All of the above
Explanation: A resistor dissipates electrical energy as heat; ideal capacitors and inductors do not dissipate average real power.
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Question #43Radio Theory and Communication Principles
The most common stage used for amplifying an electrical signal is
- Common Base
- Common collector
- Common emitter ✓ Correct answer
- Emitter follower
Explanation: The common-emitter configuration is widely used for voltage amplification.
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Question #45Radio Theory and Communication Principles
The ideal value of ripple factor should be
- 0 ✓ Correct answer
- 1
- 0.707
- 1.414
Explanation: An ideal rectifier output has zero ripple; hence the ideal ripple factor is zero.
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Question #48Radio Theory and Communication Principles
The following modulation is used for audio transmission in TV broadcast
- Amplitude modulation
- Frequency modulation ✓ Correct answer
- Pulse modulation
- None of the above
Explanation: FM is used for television sound broadcasting in the conventional analogue system.
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