" /> -->

12th Standard Physics Communication Systems English Medium Free Online Test One Mark questions 2020 - 2021

12th Standard EM

    Reg.No. :
  •  
  •  
  •  
  •  
  •  
  •  

Physics

Time : 00:20:00 Hrs
Total Marks : 20
    Answer all the questions
    20 x 1 = 20
  1. The output transducer of the communication system converts the radio signal into ________.

    (a)

    Sound

    (b)

    Mechanical energy

    (c)

    Kinetic energy

    (d)

    None of the above

  2. The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called _______.

    (a)

    Amplitude modulation

    (b)

    Frequency modulation

    (c)

    Phase modulation

    (d)

    Pulse width modulation

  3. The frequency range of 3 MHz to 30 MHz is used for

    (a)

    Ground wave propagation

    (b)

    Space wave propagation

    (c)

    Sky wave propagation

    (d)

    Satellite communication

  4. All medium wave signals received during day time use __________ wave propagation

    (a)

    surface

    (b)

    space

    (c)

    sky

    (d)

    ionosphere

  5. The radiowaves after refraction from different part of ionosphere on reaching the earth are called as

    (a)

    ground wave

    (b)

    sky waves

    (c)

    space waves

    (d)

    micro waves

  6. The audio frequency range is

    (a)

    20 Hz to 200 Hz

    (b)

    20 Hz to 2000 Hz

    (c)

    20 Hz to 200,000 Hz

    (d)

    20 Hz to 20,000 Hz

  7. In AM, the amplitude of the carrier wave is changed in accordance with that of the ________ of the signal wave.

    (a)

    frequency

    (b)

    intensity

    (c)

    phase

    (d)

    time

  8. Messages cannot be transmitted over long distances in _________ transmission.

    (a)

    FM

    (b)

    PM

    (c)

    AM

    (d)

    PCM

  9. The change in the resting frequency of a FM transmitter is called ________

    (a)

    frequency swing

    (b)

    frequency deviation

    (c)

    range offrequency

    (d)

    centre deviation

  10. Noise is a form of __________ variation.

    (a)

    time

    (b)

    phase

    (c)

    amplitude

    (d)

    frequency

  11. Resistance of any' photosensitive material is ______ to the intensity of light exposed

    (a)

    directly proportional

    (b)

    indirectly proportional

    (c)

    a constant

    (d)

    independent

  12. In a television, the picture signals are _________ modulated.

    (a)

    amplitude

    (b)

    frequency

    (c)

    phase

    (d)

    pulse-code

  13. The transmitter in a RADAR is a high power ________.

    (a)

    cyclotron oscillator

    (b)

    magnetron oscillator

    (c)

    Hartley oscillator

    (d)

    simple harmonic oscillator

  14. The greatest technical problem with an analog communication system is _________.

    (a)

    noise

    (b)

    low speed

    (c)

    low range

    (d)

    accessibility

  15. _________ is the most often used wire material.

    (a)

    Copper

    (b)

    Aluminium

    (c)

    Sulphur

    (d)

    iron

  16. The principle used for 'transmission of light signals through optical fibre is ________.

    (a)

    refraction

    (b)

    diffraction

    (c)

    polarisation

    (d)

    total internal reflection

  17. The distance of a geostationary satellite's orbit from the Earth is about _______

    (a)

    366 km

    (b)

    108 km

    (c)

    36 X 103km

    (d)

    30 m

  18. Mobile communication is easily established by _______ communication.

    (a)

    mechanical switches

    (b)

    telephone cables

    (c)

    satellite

    (d)

    optical fibres

  19. In AM receiver, if 900 kHz station is tuned, then the local oscillator will have to produce a frequency of 

    (a)

    600 kHz

    (b)

    455 kHz

    (c)

    10.7 MHz

    (d)

    1355 kHz

  20. The resting frequency of FM transmitter is 98.5MHz. The allowed minimum and maximum frequency on either side of .the centre frequency are respectively.

    (a)

    98.400 MHz and 98.600 MHz

    (b)

    98.450 MHz and 98.550 MHz

    (c)

    98.425 MHz and 98.575 MHz

    (d)

    98.425 MHz and 98.575 MHz

*****************************************

TN 12th Standard EM Physics free Online practice tests

Reviews & Comments about 12th Standard Physics Communication Systems English Medium Free Online Test One Mark questions 2020 - 2021

Write your Comment