Communication Systems MCQs Mock Test of Class 12th Physics

Welcome to your Communication Systems MCQs Mock Test of Class 12th Physics

Q1. An antenna is:

(i) Inductive

(ii) Capacitive

(iii) Resistive

(iv) A transformer

Q2. An example of point to point mode of communication is

(i) FM radio

(ii) standard FM radio

(iii) television

(iv) telephony

Q3. Audio signal cannot be transmitted because

(i) the signal has more noise

(ii) the signal cannot be amplified for distance communication

(iii) the transmitting antenna length is very small to design

(iv) the transmitting antenna length is very large and impracticable

Q4. The modulation index in amplitude modulation is:

(i) Always zero

(ii) Between 0 and 1

(iii) Between 1 and ∞

(iv) None of these

Q5. The wavelength of a wave of frequency 10 kHz is:

(i) 30 m

(ii) 300 m

(iii) 30 km

(iv) 300 km

Q6. The frequency band used in the downlink of satellite communication is

(i) 9.5 to 2.5 GHz

(ii) 896 to 901 MHz

(iii) 3.7 to 4.2 GHz

(iv) 3.7 to 4.2 MHz

Q7. How many elements are essential for any communication system?

(i) 3

(ii) 2

(iii) 4

(iv) 7

Q8. The term channel is used to indicate

(i) the amplitude range allocated to a given source

(ii) the frequency range allocated to a given source

(iii) the voltage-range allocated to a given source

(iv) All of the above

Q9. The audio frequencies range from:

(i) 20 Hz to 20.000 kHz

(ii) 20 Hz to 20 kHz

(iii) 20 kHz to 20.000 kHz

(iv) None of these

10.

Q10. A carrier frequency of 1 MHz and peak value of 10 V is amplitude modulated with a signal frequency of 10 kHz with peak value of 0.5 V. Then the modulation index and the side band frequencies respectively are

(i) 0.05 and 1 ± 0.010 MHz

(ii) 0.5 and 1 ± 0.010 MHz

(iii) 0.05 and 1 ± 0.005 MHz

(iv) 0.5 and 1 ± 0.005 MHz

11.

Q11. Which of the following is the purpose of the transmitter?

(i) Converts signals to electric form

(ii) Operating the received signal

(iii) Converting the signal into a suitable form

(iv) Reduces noise from signals

12.

Q12. The range of frequency bands used for television VHF service is

(i) 540- 1600 kHz

(ii) 88 – 108 MHz

(iii) 3.7-4.2 GHz

(iv) 54 – 72 MHz

13.

Q13. The term used “to collect the information about an object and a place without physical contact” is called :

(i) modulation

(ii) communication

(iii) amplification

(iv) remote sensing

14.

Q14. 1000 kHz carrier wave is amplitude modulated by the signal frequency 200 – 4000 Hz. The channel width of this case is

(i) 8 kHz

(ii) 4 kHz

(iii) 7.6 kHz

(iv) 3.8 kHz (e) 400 kHz

15.

Q15. Which among the following can be an input to a transmitter?

(i) Voice signal

(ii) Electric signal

(iii) Light signal

(iv) Wave signal

16.

Q16. Wave obtained on superimposition of audible frequency e.m. wave is known as

(i) carrier wave

(ii) high frequency wave

(iii) modulating wave

(iv) modulated wave

17.

Q17. Who undertook the first space walk and in which year?

(i) Leonov 1965

(ii) Neil Armstrong, 1969

(iii) Rakesh Sharma. 1998

(iv) None of these

18.

Q18. If the TV telecast is to cover a radius of 120 km (given the radius of the earth = 6400 km), the height of the transmitting antenna is

(i) 1280 m

(ii) 1125 m

(iii) 1560 m

(iv) 79 m

19.

Q19. Which of the following is the reason for signal distortion?

(i) Speed of the signal

(ii) Wearing down of the essential elements

(iii) Absence of a channel

(iv) Channel imperfection

20.

Q20. Which of the following is drawback of amplitude modulation?

(i) low efficiency

(ii) noise reception

(iii) operating range is small

(iv) all of these

21.

Q21. Which of the following is not transducer?

(i) Loudspeaker

(ii) Amplifier

(iii) Microphone

(iv) All

22.

Q22. The mobile telephones operate typically in the range of

(i) 1 – 100 MHz

(ii) 100 – 200 MHz

(iii) 1000 – 2000 MHz

(iv) 800 – 950 MHz

23.

Q23.What is the function of the receiver?

(i) Converts signal into electric form

(ii) Reducing noise during transmission

(iii) Operating on the received signal

(iv) Converting the signal into a useful form

24.

Q24. In FM, when frequency deviation is doubled, then

(i) modulation is halved

(ii) carrier swing is halved

(iii) modulation is doubled

(iv) modulation index is decreased

25.

Q25. The space waves which are affected seriously by atmospheric conditions are:

(i) MF

(ii) HUF

(iii) VHF

(iv) UHF

26.

Q26. The waves that are bent down by the ionosphere are

(i) ground waves

(ii) surface waves

(iii) sky waves

(iv) space waves

27.

Q27. Find the odd one out.

(i) Radio

(ii) Telephone

(iii) Television

(iv) Computer networking

28.

Q28. In PCM if the transmission path is very long

(i) pulse spacing is reduced

(ii) pulse amplitude is increased

(iii) pulse width is increased

(iv) repeater stations are used.

29.

Q29. Who undertook the first space walk and in which year?

(a) Leonov 1965

(b) Neil Armstrong, 1969

(d) None of these

30.

Q30. The term used “to collect the information about an object and a place without physical contact” is called :

(a) modulation

(b) communication

(d) remote sensing

31.

Q31. The velocity of electromagnetic wave is:

(a) 3 × 105 ms-1

(b) 3 × 106 ms-1

(d) 3 × 1010 ms-1

32.

Q32. The wavelength of a wave of frequency 10 kHz is:

(a) 30 m

(b) 300 m

(d) 300 km

33.

Q34. The area served by an antenna of height 100 m is:

(a) 109m²

(b) 4 × 109 m²

(d) 8 × 1010m²

34.

Q33. The audio frequencies range from:

(a) 20 Hz to 20.000 kHz

(b) 20 Hz to 20 kHz

(d) None of these

35.

Q35. Which of the following is not transducer?

(a) Loudspeaker

(b) Amplifier

(d) All

36.

Q36. The space waves which are affected seriously by atmospheric conditions are:

(a) MF

(b) HUF

(d) UHF

37.

Q37. An antenna is:

(a) Inductive

(b) Capacitive

(d) A transformer

38.

Q38. Broadcasting antenna are generally:

(a) Ommi directional type

(b) Vertical type

(d) None

39.

Q39. The modulation index in amplitude modulation is:

(a) Always zero

(b) Between 0 and 1

(d) None of these

40.

Q40. The output of a digital computer is an example of:

(a) digital signal

(b) analog signal

(d) neither (a) nor (b)

41.

Q41. Name the man who was first to place his foot on the moon and in which year:

(a) Neil Armstrong, 1969

(b) James Van A lien, 1971

(d) None of these

42.

Q42. A microphone converts:

(a) sound signals into electrical signals

(b) electrical signals into sound signals

(d) Neither (a) nor (b)

43.

Q43. A loudspeaker converts:

(a) electrical signals into sound signals

(b) sound signals into electrical signals

(d) neither (a) nor (b)

44.

Q44. The sound produced by a tuning fork is a sort of:

(a) analog signal

(b) digital signal

(d) neither (a) nor (b)

45.

Q45. The length of a half wave dipole at 30 mega-hertz is:

(a) 5 m

(b) 10 m

(d) 80 m

46.

Q46. In space communication, the sound waves can be sent from one place to another:

(a) through space

(b) through wires

(d) by superimposing it on damped electro-magnetic waves

47.

Q47. The output of a digital computer is an example of:

(a) digital signal

(b) analog signal

(d) neither (a) nor (b)

48.

Q48. Which is more advantageous?

(a) analog data communication

(b) digital data communication

(d) depends on the situation

49.

Q49. Communication channel consists of:

(a) transmission line only

(b) optical fibre only

(d) All of the above

50.

Q50. AM is used for broadcasting because:

(a) it is more noise immune than other modulation system

(b) it requires less transmitting power compare with other systems

(d) No other modulation system can provide the necessary bandwidth faithful transmission

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