Q.1
In radio and television broadcast, the information signal is in the form of
  • a) analog signal
  • b) digital signal
  • c) Both analog and digit signals
  • d) neither analog nor digital signal
Q.2
In light modulation, which characteristic of the carrier light wave is varied?
  • a)Amplitude
  • b) Frequency
  • c)Phase
  • d)intensity
Q.3
Though which mode of communication can radiowaves be sent from one Plate toanother?
  • a)Ground wave ProPagation
  • b)sky wave Propagation
  • c)Space wave ProPagation
  • d)All of the above
Q.4
Which range of Frequencies is Suitable for sky wave Propagation ?
  • a) 1 KHz to 500 KHz
  • b) 1 MHz to 2 MHz
  • c)2 MHz to 20 MHz
  • d)Above 30 MHz
Q.5
Which of the Following is not a component of communication System ?
  • a) Transmitter
  • b) Transmission channel
  • c) Noise
  • d) Receiver
Q.6
Device which transform one form of energy in to another form of energy is called a
  • a)Transducer
  • b)Transformer
  • c)Transponder
  • d)Transistor
Q.7
----- is a link between the transmitter and receiver
  • a)Microphone
  • b)Transmission Channel
  • c)transducer
  • d)telephone
Q.8
______in the receiver section are used to reduce the level of noise signal
  • a) filter circuit
  • b) Modulator
  • c)de modulator
  • d)Amplifier
Q.9
The minimum distance a up to which T.V transmission from a T.V. tower of height h canbe received is Proportional to
  • a) h1/2
  • b) h
  • c) h3/2
  • d) h2
Q.10
For an amplitude modulated wave, the maximum amplitude is found to be 9V while theminimum amplitude is found to be 3V. The modulation index is
  • a)100%
  • b)75%
  • c)50%
  • d)25%
Q.11
AM is used for broadcasting because
  • a) it is more noise innumerable than other modulation system
  • b) it requires less transmitting power compared with other system
  • c)it's avoids receiver complexity....
  • d)No other modulation system can provide the necessary band width faithful transmission
Q.12
Frequencies in the UHF range normally propagation by means of
  • a) ground waves
  • b) sky waves
  • c) surface waves
  • d) space waves
Q.13
The area to be covered for T.V telecast is doubled. Then the height to transmittingantenna will have to be
  • a)doubled
  • b) halved
  • c)quadrupled
  • d)kept unchanged
Q.14
Suppose the amplitude of modulated wave equal to the signal amplitude. Then modulation is
  • a)10%
  • b)25%
  • c)50%
  • d)100%
Q.15
Space waves are generally propagated in
  • a)UHF
  • b) VHF
  • c)HF
  • d)None of there
Q.16
If the frequency of 3 KHz has to be transmitted through amplitude modulation. Whichof the following frequency should use as a carrier frequency ?
  • a) 30 Hz
  • b) 300 Hz
  • c) 3000 Hz
  • d) 3 MHz
Q.17
The range of frequencies allotted for commercial FM radio broadcast is
  • a)88 to 108 MHz
  • b)88 to 108 KHz
  • c)8 to 88 MHz
  • d)88 to 108 GHz
Q.18
The process of super imposing signal frequency on the carrier wave is known as
  • a) transmission
  • b) reception
  • c)modulation
  • d)detection
Q.19
A T.V tower has a height 150m. What is the population density around the T.V towerif the total population covered is 50 lakh ? (Radius of earth=6.4× 106 m)
  • a) 82.6/km2
  • b) 800.6/km2
  • c)828.6/km2
  • d)876.6/km2
Q.20
If M1 and M2 are the refractive indices of the material of core and cladding of an opticalfibre, than the loss of light due to its leakage can be minimized by having
  • a) M1 > M2
  • b) M1 < M2
  • c) M1=M2
  • d) None of these
Q.21
Through which mode of propagation, the radio waves can be sent from one place toanother ?
  • a)ground wave propagation
  • b) sky wave propagation
  • c)space wave propagation
  • d)all of them
Q.22
A radio can tune to any station in the 7.5 MHz to 12 MHz band. What is thecorresponding wave length band ?
  • a)400m - 250m
  • b)40m - 25m
  • c)4m - 2.5m
  • d)None of these
Q.23
Consider an optical communication system operating at λ=800 nm . Suppose only 1% ofthe optical source frequency is the available channel bandwidth for opticalcommunication. No. of channels that can be accommodated for transmitting video T.Vsignals requiring an approximate band width of 4.5 MHz is .
  • a)3.8×1014
  • b) 3.8×1012
  • c)8.4×105
  • d)1.71×107
Q.24
A signal em=20sin 2000 πt amplitude modulates a carries wave ec=80 sin 2000 00 πt .The percentage of modulation is
  • a) 25%
  • b) 0.25%
  • c) 400%
  • d) 40%
Q.25
A transmitting antenna at the top of a tower has a height of 50m and the height of thereceiving antenna is 32m. The maximum distance between them for satisfactorycommunication in line of right mode is . Given radius of earth R=6400 km
  • a)25.29×103km
  • b)20.23×103km
  • c)45.5km
  • d)None of these.
Q.26
The characteristic impendence of a co-axial cable is between .
  • a)10Ωto 20Ω
  • b)20Ω to 30Ω
  • c)30Ω to 60Ω
  • d)50Ωto 70Ω
Q.27
In order to cover a circular region of radios 128 km, by a TV transmitter, What must bethe height of the transmitting antenna ?
  • a)79 m
  • b) 1050 m
  • c)1280 m
  • d)1560 m
Q.28
The frequency of carries wave emitted from L - C oscillator of 10 μ H inductance and1 nF capacitor is .
  • a) 1592 KHz
  • b) 1592 Hz
  • c) 1592 MHz
  • d) 159.2 Hz
Q.29
If the band width is 1.6×1012Hz , how many communication channels can be obtainedwith 16 KHz band width radio signal ?
  • a) 1015
  • b) 1011
  • c)1010
  • d)108
Q.30
A transmitter transmit a power of 10 kw when modulation is 50%. What is the powerof carrier wave ?
  • a)12 KW
  • b) 7.0 KW
  • c)8.89 KW
  • d)5.0 KW
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