Class 12 Communication Systems CBSE Questions & Answers

Class 12 · Communication Systems

This is Physics Class 12 Communication Systems CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
FM Radio set used in cars is
  • A
    a receiver
    Correct
  • B
    a channel
  • C
    a transmitter
  • D
    a repeater
2
TV set used in a typical house is
  • A
    a receiver
    Correct
  • B
    a transmitter
  • C
    a repeater
  • D
    a channel
3
Attenuation is
  • A
    decrease in signal voltage and power in the channel
    Correct
  • B
    increase in signal voltage and power in the channel
  • C
    None of these
  • D
    leveling off in signal voltage and power in the channel
4
Amplification is the
  • A
    decrease in power
  • B
    decrease in voltage
  • C
    increase in voltage or power of an electrical signal
    Correct
  • D
    decrease in voltage or power of an electrical signal
5
Range of an electronic communication system
  • A
    distance to the nearest Radio station
  • B
    is the largest distance the signal can travel
  • C
    is the largest distance between a source and a destination up to which the signal is received with sufficient strength.
    Correct
  • D
    distance to the nearest TV station
6
Bandwidth of an electronic communication system
  • A
    is number of bands in the spectrum
  • B
    is the maximum frequency at which an equipment
  • C
    is the frequency range over which an equipment operates or the portion of the spectrum occupied by the signal
    Correct
  • D
    is the minimum frequency at which an equipment
7
Modulation is
  • A
    superimposing low frequency message on a high frequency wave carrier
    Correct
  • B
    alternating low frequency message and a high frequency wave carrier
  • C
    alternating high frequency message and a low frequency wave carrier
  • D
    superimposing high frequency message on a low frequency wave carrier
8
Modulation used in radio is generally
  • A
    AM/FM
    Correct
  • B
    PM
  • C
    TDM
  • D
    FDM
9
Demodulation is
  • A
    Recovering the low frequency modulating signal from the received signal
    Correct
  • B
    Recovering the high frequency modulating signal from the received signal
  • C
    Removing the high frequency signals from the received signal
  • D
    Removing the low frequency signals from the received signal
10
Repeater is used for
  • A
    extending communication range
    Correct
  • B
    increasing the signal fidelity
  • C
    limit the frequencies in communication
  • D
    changing the language of communication
11
Repeaters used in electronic communication generally
  • A
    have a receiver only
  • B
    have a reflector
  • C
    none of these
  • D
    have a receiver transmitter pair
    Correct
12
Fourier analysis of a periodic signal implies
  • A
    periodic signal can be regarded as a superposition of sine wave signals
    Correct
  • B
    periodic signal can be regarded as the difference of sine wave signals
  • C
    periodic signal can be regarded as a division of sine wave signals
  • D
    periodic signal can be regarded as a multiplication of sine wave signals
13
Fourier series of a repeating sine wave has a
  • A
    discrete spectrum
    Correct
  • B
    none of these
  • C
    continuous spectrum
  • D
    discontinuous spectrum
14
Fourier series of a periodic rectangular pulse has a
  • A
    discontinuous spectrum
  • B
    none of these
  • C
    discrete spectrum
  • D
    continuous spectrum
    Correct
15
Fourier series of a periodic rectangular wave has a
  • A
    continuous spectrum
  • B
    discrete spectrum
    Correct
  • C
    none of these
  • D
    discontinuous spectrum