# IIT JEE/IIT JEE Principles Of Communication set-1 Sample Test,Sample questions

## Question: ```7.Ring modulator is used to produce ```

1.FM

2.SSB

3.DSB-SC

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```A 400 W carrier AM modulated to a depth of 75%. The total power of the system is ```

1.512 W

2.200 W

3.450 W

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```A 500 W carrier is amplitude modulated with modulation index of 60%. What will be total power of modulated wave ```

1.640.5 W

2.590 W

3.780 W

4.450 W

Posted Date:-2021-09-20 17:46:22

## Question: ```A glass coating surrounding the glass core in an optical fibre is called ```

1.Coating

2.Mixing

3.Modulating

Posted Date:-2021-09-20 17:46:22

## Question: ```A radiowave signal propagating from one point to other following the surface of Earth is called ```

1.sky wave

2.ultrasonic wave

3.sound wave

4.ground wave

Posted Date:-2021-09-20 17:46:22

## Question: ```Absorption of radiowaves by atmosphere depends upon ```

1.distance from transmitter

2.polarization of wave

3.polarization of atmosphere

4.frequency

Posted Date:-2021-09-20 17:46:22

## Question: ```Audio signal can t be directly transmitted into the space because ```

1.Audio signals can t propagate through air

2.Audio signals are high frequency signal

3.Audio signal need some external help for propagation

4.A very high antenna is needed for their propagation

Posted Date:-2021-09-20 17:46:22

## Question: ```Balance modulator is used to produce ```

1.DSB-SC

2.SSB

3.VSB

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Base band pulses travels ```

1.Along wires

2.In space

3.In wave guides

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Bit rate is given by ```

1.sampling rate + number of bits per cycle

2.sampling rate/number of bits per cycle

3.sampling rate * number of bits per cycle

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Broadcast band in which FM lies is ```

1.UHF

2.VHF

3.SHF

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Crystal oscillator is used to generate carrier waves because of ```

1.good stability

2.high power output no buffer stage is

3.required

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Data communicated by optical fibres system is generally ```

1.digital

2.analog

3.modulated

4.unmodulated

Posted Date:-2021-09-20 17:46:22

## Question: ```Demodulation ```

1.is done at the transmitting stations

2.is done at the receiving station

3.removes side bands

4.rectifies modulated signal

Posted Date:-2021-09-20 17:46:22

## Question: ```Dibits in PM are ```

1.Two-phase signals

2.Four-frequency signals

3.Four-phase signals

4.Two-frequency signals

Posted Date:-2021-09-20 17:46:22

## Question: ```he digital transmission is done mostly via None of these```

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```If 100% modulation is produced in AM then ```

1.carrier frequency is equal to signal frequency

2.carrier frequency exceeds signal frequency amplitude exceeds signal

3.amplitude

4.amplitude equals signal amplitude

Posted Date:-2021-09-20 17:46:22

## Question: ```If AM having 100% modulation of the total transmitted power each side band carries ```

1.one third

2.one half

3.one fourth

4.one sixth

Posted Date:-2021-09-20 17:46:22

## Question: ```If carrier frequency is 100 kH and modulating frequency is 5kH then band width of AM transmission is ```

1.10

2.20

3.50

4.80

Posted Date:-2021-09-20 17:46:22

## Question: ```If the frequency of EM radiations is halved then the energy of EM radiation will become ```

1.double

2.remains unchanged

3.becomes half

4.becomes one fourth

Posted Date:-2021-09-20 17:46:22

## Question: ```If the ratio of wavelength emitted from two different sources is 1 : 2 then ratio of their velocities will be None of these```

1.1:01

2.1:02

3.2:01

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In a true WBFM all the energy is associated with None of these```

1.Side bands

2.Carrier terms

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In AM if modulation index is more than 100% then ```

1.The wave gets distorted

2.Efficiency increases

3.Power increases

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In AM transmission which modulator is being used ? ```

1.Class-C modulator

2.Class-A modulator

3.Class-B modulator

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In AM wave the modulation index is 100% If the carrier is suppressed the percentage saving in power will be ```

1.66.60%

2.50%

3.75%

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In amplitude modulated wave power content of the carrier is maximum when A17m is ```

1.0

2.5

3.0.3

4.0.4

Posted Date:-2021-09-20 17:46:22

## Question: ```In an AM system full information can be conveyed by transmitting only ```

1.the lower side band

2.the upper side band

3.any one side band

4.the carrier

Posted Date:-2021-09-20 17:46:22

## Question: ```In an AM transmission band width is equal to ```

1.maximum frequency of audio signal

2.minimum frequency of audio signal

3.twice the maximum frequency of audio signal

4.half the maximum frequency of audio signal

Posted Date:-2021-09-20 17:46:22

## Question: ```In FM if frequency deviation is doubled ```

1.modulation is doubled

2.modulation remains unchanged

3.modulation is halved

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```In optical fibre propagation angle of light must be less than or equal to ```

1.incident angle

2.refraction angle

3.reflection angle

4.critical angle

Posted Date:-2021-09-20 17:46:22

## Question: ```Intelsat satellite is used in ```

1.Intercontinental communication

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Intelsat satellite works as a ```

1.absorber

2.repeater

3.transmitter

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Lasers are used as an endoscope in which field ? ```

1.Medical

2.Scientific

3.Communication

4.Entertainment

Posted Date:-2021-09-20 17:46:22

## Question: ```Lasers are used in alignment of pipes because ```

1.they are coherent

2.they are highly directional

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Modulation index in FM depends upon ```

1.Amplitude of modulating signal

2.Frequency of modulating signal

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Optical fibra communication have an advantage over general communication because ```

1.It is more efficient

2.Of security of signal

3.Of both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Optical fibres made of glass or plastic are ```

1.brittle

2.leaky

3.fragile

4.insulators

Posted Date:-2021-09-20 17:46:22

## Question: ```Out of following which wave disappears because of tilting ? ```

1.Space waves

2.Microwaves

3.Sky waves

4.Surface waves

Posted Date:-2021-09-20 17:46:22

## Question: ```Out of the following subsystems which is used for satellite or+A68bit position and altitude ```

1.Antenna subsystem

2.Thrust subsystem

3.Stabilization subsystem

4. Power subsystem

Posted Date:-2021-09-20 17:46:22

## Question: ```Out of the following which is not a correct statement for FM ? ```

1.Total power remain constant w. r. t. modulation index

2.Carrier never becomes zero

3.-coefficients are occasionally negative

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Out of the following which is not a correct statement for FM ? ```

1.Modulate the digital signals

2.Covert analog signals to digital ones

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Out of the following which type of sampling is preferred ? ```

1.Non-uniform

2.Uniform

3.Linear

4.Both (b) and C

Posted Date:-2021-09-20 17:46:22

## Question: ```Purpose of modulator is ```

1.to increase the energy of carrier

2.to impress the information on carrier

3.to separate the carrier and information

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Satellite used for only reflecting back the signal to earth stations is called ```

1.Passive satellite

2.Neutral satellite

3.Active satellite

4.Natural satellite

Posted Date:-2021-09-20 17:46:22

## Question: ```Select the incorrect statement ```

1.FM receptions is quite immune the noise

2.Efficiency of FM transmission if high

3.High fidelity reception is obtained in FM

4.FM signals can be easily coded

Posted Date:-2021-09-20 17:46:22

## Question: ```Select the wrong statement in case of EM waves. ```

1.EM waves are transverse in nature

2.Travel in free space at a speed of light

3.Are produced by accelerating charges

4.Travel in all media with same speed.

Posted Date:-2021-09-20 17:46:22

## Question: ```Space waves normally propagated in ```

1.UHF

2.SHF

3.HF

4.VHF

Posted Date:-2021-09-20 17:46:22

## Question: ```The antenna current of an AM transmission is 8A when only carrier is sent but is increases to 893 A when the carrier is modulate The modulation of the wave is ```

1.43%

2.60%

3.57%

4.Power subsystem

Posted Date:-2021-09-20 17:46:22

## Question: ```The carrier suppression is done son as to ```

1.minimize the cost

2.simple the design

3.never done practically

4.All of the above

Posted Date:-2021-09-20 17:46:22

## Question: ```The circuits that produces PDM requires ```

1.Save tooth wave generator

2.Clipping and squaring circuits

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The disadvantage of FM over AM is ```

1.Noise is very high for high frequency signals

2.High modulation power is required

3.Larger band width is required

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The DSB-SC signal are detected by ```

1.Reinecting the carrier

2.Removing the carrierr

3.Removing one side band

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The fading process applies to ```

1.Atmospheric storm

2.Ionospheric propagation

4.Troposcatter propagation

Posted Date:-2021-09-20 17:46:22

## Question: ```The frequency used in TV and radar system lies in ```

1.VHF

2.UHF

3.UHF

4.VLF

Posted Date:-2021-09-20 17:46:22

## Question: ```The layer that absorbs largest proportion of UV rays is ```

1.Ozone layer

2.Isoposphere

3.Ionosphere

4.Mesosphere

Posted Date:-2021-09-20 17:46:22

## Question: ```The loop gain in case of two wire repeater is must be ```

1.greater than 1

2.equal to 1

3.less than 1

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The modulation index in case of FM is defined for ```

1.Multi-tone modulation

2.Tone-modulation only

3.All types of modulating signals

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The modulation index of an ores-modulated wave is ```

1.Less than 1

2.Equal to 1

3.Greater than 1

4.Infinite

Posted Date:-2021-09-20 17:46:22

## Question: ```The number of AM broadcast stations that can be accommodated in a 300 kHz band w+A65idth for the highest modulating frequency 15 kHz will be ```

1.10

2..In optical fibre propagation angle of light must be less than or equal to

3.7

4.12

Posted Date:-2021-09-20 17:46:22

## Question: ```The process in which the wave follows the Earth s curvature is called as ```

2.Windowing

3.Dusting

4.Ionospheric reflection

Posted Date:-2021-09-20 17:46:22

## Question: ```The product demodulator is also known as ```

1.Balance demodulator

2.SSB demodulator

3.Amplitude discriminator

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The product modulator basically is a ```

1.Mixer

2.Ampliffer

3.Balanced modulator

4.Frequency separator

Posted Date:-2021-09-20 17:46:22

## Question: ```The region that contains free electrons and negative ions and positive ions and positive ions is ```

1.Isoposphere

2.Mesophere

3.Ionosphere

4.Stratosphere

Posted Date:-2021-09-20 17:46:22

## Question: ```The sampling rate lies between ```

1.W to 2W

2.0 to W

3.0 to 2W

4.2W to 4W

Posted Date:-2021-09-20 17:46:22

## Question: ```The satellite that seems stationary w r t Earth is ```

1.Intelsat

2.Geostationary satellite

3.Telstar

4.Marisat

Posted Date:-2021-09-20 17:46:22

## Question: ```The threshold in FM depends upon ```

1.Frequency deviation

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The total channel band width allotted to FM is ```

1.100 KHz

2.75 KHz

3.300 KHz

4.200 KHz

Posted Date:-2021-09-20 17:46:22

## Question: ```The total power contact of an AM wave is 1200 W. What will be modulation index if each side band contains 150 W of power ```

1.81.60%

2.60%

3.75%

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The transmission band width in WBFM is ```

1.Independent of message band width

2.Dependent of message band width

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```The waves that are related to telecommunication are ```

1.Ultra-violet

2.Microwaves

3.Infra-red

4.Visible light

Posted Date:-2021-09-20 17:46:22

## Question: ```Tropospheric scatter happens in ```

1.VHF

2.UHF

3.HF

4.SHF

Posted Date:-2021-09-20 17:46:22

## Question: ```Voice communication is done by using ```

1.SSB

2.DSB-SC

3.Both (a) and (b)

4.None of these

Posted Date:-2021-09-20 17:46:22

## Question: ```Wavelength of the waves having frequency 3000 MHz is ```

1.10 cm

2.50 cm

3.100 cm

4.150 cm

Posted Date:-2021-09-20 17:46:22

## Question: ```Waves used for long distance broadcast are ```

1.short waves

2.long waves

3.light waves

4.any waves

Posted Date:-2021-09-20 17:46:22

## Question: ```Which of the following waves gets affected by solar cycle ? ```

1.Very low frequency

2.High frequency

3.Low frequency

4.Very high frequency

Posted Date:-2021-09-20 17:46:22

## More MCQS

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