Tag: electromagnetic waves and communication system

Questions Related to electromagnetic waves and communication system

Generation, propagation and detection of electromagnetic waves is the basis of

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. lasers

  2. reactors

  3. radio and television

  4. computer

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Correct Option: C
Explanation:

The communication and broadcasting following the base on generation, propagation, and detection of electromagnetic waves.

The electromagnetic spectrum describes a different range of electromagnetic waves. These EM waves are a special type of wave that can travel without a medium.

Electromagnetic waves are named like this due to the fact that they have both an electric and a magnetic component. In a vacuum, EM waves always travel at the same speed i.e. the speed of light. So, other EM waves besides light are infrared, ultraviolet, radio waves, and microwaves. Therefore radio and television both are based on EM wave properties. Other options like lasers, reactors, and computers are not guided by EM waves.

Thus the correct option is C. 

The attenuation of a signal is compensated by

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. rectifier

  2. oscillator

  3. modulator

  4. amplifier

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Correct Option: D
Explanation:

Attenuation means reduction of strength of signal, thus signals are to be amplified.

A transducer used at the transmitting end, serves the purpose of converting

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. electrical signal to sound form

  2. sound signal to electrical form

  3. electrical signal to magnetic form

  4. sound signal to magnetic form

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Correct Option: B
Explanation:

In this case transducer takes the sound signal and convert them to electrical signal.

During the process of modulation the RF wave is called

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. Modulating wave

  2. Modulated wave

  3. Carrier wave

  4. Audio wave

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Correct Option: C
Explanation:

Signals which need to be transferred are superimposed on high frequency wave, which is called carrier wave, as the name suggests it carries the signals.

Loudspeaker is a transducer used at

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. receiving end.

  2. transmitting end.

  3. both (A) and (B).

  4. neither (A) nor (B).

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Correct Option: A
Explanation:

Loudspeaker is a transducer which converts electrical signal transmitted by the transmitter to sound form at the receiving end.

A transducer used at the transmitting end, serves the purpose of converting

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. electrical signal to sound form

  2. sound signal to electrical form

  3. electrical signal to magnetic form

  4. sound signal to magnetic form

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Correct Option: B
Explanation:

The message from the information source may not be in electrical form, so to convert these information, i.e., in form of sound to electrical form, a transducer like a microphone is used.

Reception of information involves

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. decoding of signal.

  2. storage of signal.

  3. interpretation of signal.

  4. all of the above.

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Correct Option: D
Explanation:

The received signals is either AM or FM so it needs to be demodulated, ie., decoded to get back original signal. It also needs to be stored and interpreted at receiving end.

Main function of the RF amplifiers in a superheterodyne receiver is to

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. amplify signal

  2. reject unwanted signal

  3. discriminate against image frequency signal and IF-signal

  4. all of the above

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Correct Option: D
Explanation:

A superheterodyne receiver is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency.

The antenna collects the radio signal. The tuned RF stage with optional RF amplifier provides some initial selectivity, and may also serve to prevent strong out-of-passband signals from saturating the initial amplifier.A local oscillator provides the mixing frequency; it is usually a variable frequency oscillator which is used to tune the receiver to different stations. The frequency mixer does the actual heterodyning, it changes the incoming radio frequency signal to a higher or lower, fixed, intermediate frequency(IF). The IF band pass filter and amplifier supply most of the gain and the narrowband filtering for the radio. The demodultor extracts the audio or other modulation from the IF radio frequency; the extracted signal is then amplified by the audio amplifier.

A carbon microphone is best used in a

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. dynamo

  2. telephone

  3. transformer

  4. none of these

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Correct Option: B
Explanation:
The telephone uses a carbon microphone . It is a transducer that converts the sound into elecrical audio signal.It consits of two metal plates seperated by granules of carbon-one plate is very thin and faces toward the speaking person,acting as a diaphragm.

"Man-made" noise can come from:

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. equipment that sparks

  2. temperature

  3. static

  4. all of the above

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Correct Option: A
Explanation:

Man-made noise is a noise created due to wear and tear of electrical machinery used in transmission systems. They are due to the type of amplifiers (class B) type of pulses (wideband pulses), often caused by ignition circuits, lightning, and switching elements causing spark gaps