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Physics - Communication System

Practise 107 JEE Main previous year questions on Communication System, compiled from papers spanning 2003 to 2023. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty JEE Main tests.

Communication System has been asked in 14 of the 25 years of JEE Main papers analysed (2002–2026), with 107 questions in all. 63% of them were easy, 28% moderate and 9% tough. Most of its questions came from 2021, with 24 questions that year. In the last three years (2024–2026) it had 0 questions across 49 papers, about 0 per paper.

The chapter's 3 topics are not weighted equally: Modulation (60 questions, 56%), Communication System (38 questions, 36%), and Propagation of EM Waves (9 questions, 8%) have been asked the most. Modulation has also led over the last five years, with 28 questions. Modulation has produced the most tough questions (5).

  1. 1The height of transmitting antenna is 180 m and the height of the receiving antenna is 245 m . The maximum distance between them for satisfa15 Apr, 2023 (M)Modulation
  2. 2Match List-I with List-II List-I (Layer of atmosphere) List-II (Approximate height over earth s surface) ( A ) F 1 - Layer ( I ) 10 km B D -13 Apr, 2023 (M)Communication System
  3. 3To radiate EM signal of wavelength with high efficiency, the antennas should have a minimum size equal to:13 Apr, 2023 (E)Modulation
  4. 4The amplitude of 15 sin ( 1000 t ) is modulated by 10 sin ( 4 t ) signal. The amplitude modulated signal contains frequencies of A. 500 Hz B12 Apr, 2023 (M)Modulation
  5. 5A transmitting antenna is kept on the surface of the earth. The minimum height of receiving antenna required to receive the signal in line o11 Apr, 2023 (M)Modulation
  6. 6In satellite communication, the uplink frequency band used is:11 Apr, 2023 (E)Communication System
  7. 7A carrier wave of amplitude 15 V is modulated by a sinusoidal base band signal of amplitude 3 V . The ratio of maximum amplitude to minimum 10 Apr, 2023 (M)Modulation
  8. 8A massage signal of frequency 3 kHz is used to modulate a carrier signal of frequency 1 . 5 MHz . The bandwidth of the amplitude modulated w10 Apr, 2023 (E)Modulation
  9. 9A TV transmitting antenna is 98 m high and the receiving antenna is at the ground level. If the radius of the earth is 6400 km , the surface08 Apr, 2023 (M)Modulation
  10. 10The power radiated from a linear antenna of length l is proportional to (Given, = Wavelength of wave):08 Apr, 2023 (E)Modulation
  11. 11By what percentage will the transmission range of a TV tower be affected when the height of the tower is increased by 21 % ?06 Apr, 2023 (M)Modulation
  12. 12For an amplitude modulated wave the minimum amplitude is 3 V , while the modulation index is 60 % . The maximum amplitude of the modulated w06 Apr, 2023 (E)Modulation
  13. 13Which of the following frequencies does not belong to FM broadcast.01 Feb, 2023 (M)Communication System
  14. 14In an amplitude modulation, a modulating signal having amplitude of X V is superimposed with a carrier signal of amplitude Y V in first case01 Feb, 2023 (E)Modulation
  15. 15The amplitude of 15 sin ( 1000 t ) is modulated by 10 sin ( 4 t ) signal. The amplitude modulated signal contains frequency (ies) of ( A ) 531 Jan, 2023 (M)Modulation
  16. 16Given below are two statements Statement I : For transmitting a signal, size of antenna ( l ) should be comparable to wavelength of signal (31 Jan, 2023 (E)Modulation
  17. 17A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of 120 V and 830 Jan, 2023 (M)Modulation
  18. 18Match List I with List II List I List II A Attenuation I Combination of a receiver and transmitter B Transducer II Process of retrieval of i30 Jan, 2023 (E)Communication System
  19. 19If the height of transmitting and receiving antennas are 80 m each, the maximum line of sight distance will be : Given : Earth s radius = 6 29 Jan, 2023 (M)Propagation of EM Waves
  20. 20The modulation index for an A.M. wave having maximum and minimum peak to peak voltages of 14 mV and 6 mV respectively is :29 Jan, 2023 (E)Modulation
  21. 21A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz . The bandwidth for amplitude modulation is:25 Jan, 2023 (M)Modulation
  22. 22A modulating signal is a square wave, as shown in the figure. If the carrier wave is given as c t = 2 sin 8 t volts, the modulation index is24 Jan, 2023 (M)Modulation
  23. 23Match List I with List II LIST I LIST II A AM Broadcast I 88 - 108 MHz B FM Broadcast II 540 - 1600 kHz C Television III 3 . 7 - 4 . 2 GHz D24 Jan, 2023 (E)Communication System
  24. 24Find the modulation index of an AM wave having 8 V variation where maximum amplitude of the AM wave is 9 V .29 Jul, 2022 (M)Modulation
  25. 25A modulating signal 2 sin 6 . 28 10 6 t is added to the carrier signal 4 sin 12 . 56 10 9 t for amplitude modulation. The combined signal is29 Jul, 2022 (E)Modulation
  26. 26In the case of amplitude modulation to avoid distortion the modulation index should be :28 Jul, 2022 (M)Modulation
  27. 27A FM Broad cast transmitter, using modulating signal of frequency 20 kHz has a deviation ratio of 10 . The Bandwidth required for transmissi28 Jul, 2022 (E)Communication System
  28. 28At a particular station, the TV transmission tower has a height of 100 m . To triple its coverage range, height of the tower should be incre27 Jul, 2022 (M)Communication System
  29. 29A square wave of the modulating signal is shown in the figure. The carrier wave is given by C t = 5 sin 8 t Volt. The modulation index is27 Jul, 2022 (E)Modulation
  30. 30A radio can tune to any station in 6 MHz to 10 MHz band. The value of corresponding wavelength bandwidth will be26 Jul, 2022 (M)Communication System
  31. 31The maximum and minimum voltage of an amplitude modulated signal are 60 V and 20 V respectively. The percentage modulation index will be26 Jul, 2022 (E)Modulation
  32. 32The required height of a TV tower which can cover the population of 6 . 03 lakh is h . If the average population density is 100 per square k25 Jul, 2022 (M)Communication System
  33. 33In AM modulation, a signal is modulated on a carrier wave such that maximum and minimum amplitude are found to be 6 V and 2 V respectively. 25 Jul, 2022 (E)Modulation
  34. 34Only 2 % of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm . If an29 Jun, 2022 (M)Communication System
  35. 35The TV transmission tower at a particular station has a height of 125 m . For doubling the coverage of its range, the height of the tower sh29 Jun, 2022 (E)Modulation
  36. 36Match List-I with List-II List-I List-II (A) Television signal I. 03 KHz (B) Radio signal II. 20 KHz (C) High Quality Music III. 02 MHz (D) 28 Jun, 2022 (M)Communication System
  37. 37Amplitude modulated wave is represented by V AM = 10 1 + 0 . 4 cos 2 10 4 t cos 2 10 7 t . The total bandwidth of the amplitude modulated wa28 Jun, 2022 (E)Communication System
  38. 38The height of a transmitting antenna at the top of a tower is 25 m and that of receiving antenna is, 49 m . The maximum distance between the27 Jun, 2022 (M)Communication System
  39. 39We do not transmit low frequency signal to long distances because (a) The size of the antenna should be comparable to signal wavelength whic27 Jun, 2022 (E)Communication System
  40. 40Choose the correct statement for amplitude modulation26 Jun, 2022 (M)Modulation
  41. 41A sinusoidal wave y t = 40 sin 10 10 6 t is amplitude modulated by another sinusoidal wave x t = 20 sin 1000 t . The amplitude of minimum fr26 Jun, 2022 (E)Modulation
  42. 42A signal of 100 THz frequency can be transmitted with maximum efficiency by25 Jun, 2022 (M)Communication System
  43. 43Match List I with List II List I List II (A) Facsimile (I) Static Document Image (B) Guided media Channel (II) Local Broadcast Radio (C) Fre25 Jun, 2022 (E)Communication System
  44. 44A baseband signal of 3 . 5 MHz frequency is modulated with a carrier signal of 3 . 5 GHz frequency using amplitude modulation method. What s24 Jun, 2022 (M)Modulation
  45. 45An antenna is placed in a dielectric medium of dielectric constant 6 . 25 . If the maximum size of that antenna is 5 . 0 mm , it can radiate24 Jun, 2022 (E)Modulation
  46. 46A carrier wave with amplitude of 250 V is amplitude modulated by a sinusoidal base band signal of amplitude 150 V . The ratio of minimum amp01 Sep, 2021 (E)Modulation
  47. 47If the sum of the heights of transmitting and receiving antennas in the line of sight of communication is fixed at 160 m , then the maximum 31 Aug, 2021 (M)Communication System
  48. 48A bandwidth of 6 MHz is available for A . M . transmission. If the maximum audio signal frequency used for modulating the carrier wave is no31 Aug, 2021 (E)Communication System
  49. 49A transmitting antenna has a height of 320 m and that of receiving antenna is 2000 m . The maximum distance between them for satisfactory co27 Aug, 2021 (M)Propagation of EM Waves
  50. 50An antenna is mounted on a 400 m tall building. What will be the wavelength of signal that can be radiated effectively by the transmission t27 Aug, 2021 (E)Communication System

Frequently Asked Questions

1.How many questions are available for Communication System?

This chapter includes 107 questions compiled from JEE Main papers spanning 2003 to 2023.

2.Are these questions only from JEE Main, or from other exams too?

These are JEE Main questions specifically for the Communication System chapter. Questions from other exams like NTA Abhyas (JEE Main) or JEE Advanced are organised separately under their respective exam sections.

3.Is Communication System an important chapter for JEE Main Physics?

Communication System has appeared in 14 of the 25 years of JEE Main papers covered here, with 107 questions across 107 papers - about one per paper it appears in.

4.What is the difficulty level of Communication System questions in JEE Main?

Of the 107 questions analysed for this chapter, 63% are easy, 28% moderate and 9% tough. 2021 had the most, with 24 questions.

5.Which topics in Communication System should I focus on?

These topics have carried the most weightage in Communication System:

  • Modulation - 60 questions (56%)
  • Communication System - 38 questions (36%)
  • Propagation of EM Waves - 9 questions (8%)
  • Modulation has produced the most tough questions (5).
6.Is Communication System's weightage in JEE Main going up or down?

Across all 107 papers analysed, Communication System has averaged about 1.0 questions per paper. In the last three years (2024–2026), that average has fallen, at about 0.0 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.