JEE Physics Communication System MCQs Set 09

Multiple Choice Questions (MCQs) for JEE Physics: Communication System

Explore reliable objective questions for Communication System tailored for JEE learners. Utilizing these Physics multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Practice Communication System MCQs for JEE Physics

Access the complete set of multiple-choice questions for Communication System below. This focused format allows students to isolate specific topics for thorough review and uninterrupted practice alongside official JEE textbooks.

Multiple Choice Questions

Question 1: Audio signal cannot be transmitted because
(a) the signal has more noise
(b) the signal cannot be amplified for distance communication
(c) the transmitting antenna length is very small to design
(d) the transmitting antenna length is very large and impracticable
Show Answer & Explanation

Answer: (d) the transmitting antenna length is very large and impracticable

Explanation:
1. The antenna would have to be several kilometres long.

Teacher's Note:
1. Recall the basic fact.

Question 2: In sky-wave propagation, skip-distance depends on
(a) frequency of e.m. waves transmitted
(b) critical frequency of the layer
(c) height of layer above earth's surface
(d) all of the above
Show Answer & Explanation

Answer: (d) all of the above

Explanation:
1. D_skip = 2h√((f/fc)² − 1) depends on h, f and fc.

Teacher's Note:
1. Recall the basic fact.

Question 3: Calculate the power developed by an amplitude modulated wave in a load resistance of 100 Ω, if the peak voltage of carrier wave is 100 V and modulation index is 0.4.
(a) 50 watt
(b) 54 watt
(c) 104 watt
(d) 4 watt
Show Answer & Explanation

Answer: (b) 54 watt

Explanation:
1. Carrier power = V²/2R = 10⁴/200 = 50 W.
2. Total = 50(1 + 0.16/2) = 54 W.

Teacher's Note:
1. Recall the basic fact.

Question 4: The frequency deviation in a FM transmission is 18.75 kHz. If it broadcasts in 88–108 MHz band, then the percent modulation is (maximum allowed deviation is 75 kHz)
(a) 10%
(b) 25%
(c) 50%
(d) 75%
Show Answer & Explanation

Answer: (b) 25%

Explanation:
1. Percent modulation = 18.75/75 = 25%.

Teacher's Note:
1. Recall the basic fact.

Question 5: Long range transmission of TV-signal is done by
(a) space-wave
(b) sky waves
(c) ground wave
(d) artificial satellite
Show Answer & Explanation

Answer: (d) artificial satellite

Explanation:
1. TV signals are not reflected by the ionosphere, so satellites relay them over long distances.

Teacher's Note:
1. Recall the basic fact.

Question 6: Space wave communication is limited
(a) to the line of sight distance
(b) by earth's curvature
(c) either (a) or (b)
(d) both (a) and (b)
Show Answer & Explanation

Answer: (d) both (a) and (b)

Explanation:
1. The range is limited by the line of sight, which is set by the curvature of the earth.

Teacher's Note:
1. Recall the basic fact.

Question 7: In space communication, the sound waves can be sent from one place to another
(a) through space
(b) through wires
(c) by superimposing it on undamped electromagnetic waves
(d) by superimposing it on damped electromagnetic waves
Show Answer & Explanation

Answer: (c) by superimposing it on undamped electromagnetic waves

Explanation:
1. The audio is superimposed on a continuous (undamped) carrier wave.

Teacher's Note:
1. Recall the basic fact.

Question 8: For a radio wave reaching the ionised medium
(a) will bend away from normal
(b) will bend towards normal
(c) will follow a straight-path
(d) None of these
Show Answer & Explanation

Answer: (a) will bend away from normal

Explanation:
1. Refractive index of the ionosphere is below 1, so the wave bends away from the normal.

Teacher's Note:
1. Recall the basic fact.

Question 9: Match the layers of the atmosphere (Column I) with the frequencies most affected (Column II).
Column IColumn II
(A) Troposphere(1) Efficiently reflects HF waves
(B) Stratosphere(2) Partially absorbs HF waves
(C) Mesosphere(3) V H F up to several GHz
(D) Thermosphere(4) Reflects LF absorbs MF and HF to some degree

(a) A-1, B-2, C-4, D-3
(b) A-3, B-2, C-4, D-1
(c) A-3, B-1, C-4, D-2
(d) A-4, B-2, C-3, D-1
Show Answer & Explanation

Answer: (b) A-3, B-2, C-4, D-1

Explanation:
1. VHF waves pass through the troposphere.
2. The stratosphere partially absorbs HF.
3. The mesosphere reflects LF and absorbs MF and HF.
4. The thermosphere (ionosphere) reflects HF.

Teacher's Note:
1. Different layers act on different frequency bands.

Question 10:
Assertion (A): Space waves are used for line-of-sight communication.
Reason (R): Space wave travels in a straight line from transmitting antenna to receiving antenna.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (a) Both A and R are true, and R is the correct explanation of A.

Explanation:
1. Because the waves travel in a straight line, the stations must be in line of sight.

Teacher's Note:
1. Compare the two statements.

Question 11: The picture signal in TV-broadcast is modulated in
(a) SSB
(b) VSB
(c) FM
(d) DSB
Show Answer & Explanation

Answer: (b) VSB

Explanation:
1. Vestigial sideband modulation is used for the TV picture signal.

Teacher's Note:
1. Recall the basic fact.

Question 12: Bandwidth of optical fibre communication is
(a) 10⁶ to 10⁹ Hz
(b) 10¹³ to 10¹⁵ Hz
(c) 10⁹ to 10¹¹ Hz
(d) none of these
Show Answer & Explanation

Answer: (b) 10¹³ to 10¹⁵ Hz

Explanation:
1. Optical frequencies are about 10¹³ to 10¹⁵ Hz.

Teacher's Note:
1. Recall the basic fact.

Question 13: In an ionized medium, the phase velocity vp, group velocity vg and the speed of light are related as
(a) vp > vg > c
(b) vp = vg = c
(c) vp < vg < c
(d) vp > c, vg < c
Show Answer & Explanation

Answer: (d) vp > c, vg < c

Explanation:
1. In an ionised medium vp·vg = c², so vp > c and vg < c.

Teacher's Note:
1. Recall the basic fact.

Question 14: The term channel is used to indicate
(a) the amplitude range allocated to a given source
(b) the frequency range allocated to a given source
(c) the voltage-range allocated to a given source
(d) All of the above
Show Answer & Explanation

Answer: (b) the frequency range allocated to a given source

Explanation:
1. A channel is the band of frequencies assigned to a given signal.

Teacher's Note:
1. Recall the basic fact.

Question 15: The cellular mobile radio frequency band is
(a) 88–108 MHz
(b) 54–72 MHz
(c) 540–1600 kHz
(d) 840–935 MHz
Show Answer & Explanation

Answer: (d) 840–935 MHz

Explanation:
1. Cellular mobile services use bands around 840 to 935 MHz.

Teacher's Note:
1. Recall the basic fact.

Question 16: Reception of information involves
(a) decoding of signal
(b) storage of signal
(c) interpretation of signal
(d) All of the above
Show Answer & Explanation

Answer: (d) All of the above

Explanation:
1. Reception involves demodulating, storing and interpreting the signal.

Teacher's Note:
1. Recall the basic fact.

Question 17: The losses in transmission lines are
(a) radiation losses only
(b) conductor heating only
(c) dielectric heating only
(d) all of these
Show Answer & Explanation

Answer: (d) all of these

Explanation:
1. All of these losses occur.

Teacher's Note:
1. Recall the basic fact.

Question 18: For a single side band transmission a balanced modulator is used to
(a) increase power of carrier wave
(b) increase amplitude of carrier wave
(c) suppress audio signal
(d) suppress carrier component
Show Answer & Explanation

Answer: (d) suppress carrier component

Explanation:
1. A balanced modulator cancels the carrier, leaving the sidebands.

Teacher's Note:
1. Recall the basic fact.

Question 19: If a number of sine waves with modulation indices n₁, n₂, n₃ ... modulate a carrier wave, then the total modulation index (n) of the wave is
(a) \( n_1+n_2+\ldots \)
(b) \( \sqrt{n_1-n_2+n_3\ldots} \)
(c) \( \sqrt{n_1^2+n_2^2+n_3^2+\ldots} \)
(d) \( \sqrt{n_1+n_2+\ldots} \)
Show Answer & Explanation

Answer: (c) \( \sqrt{n_1^2+n_2^2+n_3^2+\ldots} \)

Explanation:
1. The total modulation index is m = √(m₁² + m₂² + m₃² + ...).

Teacher's Note:
1. Recall the basic fact.

Question 20: Sky wave propagation is not possible for waves of frequency > 30 MHz because
(a) these waves do not have much energy to reach ionosphere
(b) they are not reflected by ionosphere
(c) they get absorbed by troposphere
(d) they get reflected by stratosphere
Show Answer & Explanation

Answer: (b) they are not reflected by ionosphere

Explanation:
1. Waves above 30 MHz penetrate the ionosphere instead of being reflected.

Teacher's Note:
1. Recall the basic fact.

Question 21: Buffer amplifier is used at the transmitting end to
(a) feed carrier frequency to master oscillator
(b) amplify carrier frequency
(c) mix modulating signal with carrier frequency
(d) isolate master oscillator from other stages of transmitter
Show Answer & Explanation

Answer: (d) isolate master oscillator from other stages of transmitter

Explanation:
1. It isolates the master oscillator from the effect of later stages such as the modulator.

Teacher's Note:
1. Recall the basic fact.

Question 22: A device with input x(t) and output y(t) is characterized by y(t) = x²(t). An FM signal with frequency deviation of 90 kHz and modulating signal bandwidth of 5 kHz is applied to this device. The bandwidth of the output signal is
(a) 370 kHz
(b) 190 kHz
(c) 380 kHz
(d) 95 kHz
Show Answer & Explanation

Answer: (c) 380 kHz

Explanation:
1. Input bandwidth = 2(90 + 5) = 190 kHz.
2. Squaring doubles the frequency deviation and bandwidth, giving 380 kHz.

Teacher's Note:
1. Recall the basic fact.

Question 23: Of the following which is preferred modulation scheme for digital communication?
(a) Pulse Code Modulation (PCM)
(b) Pulse Amplitude Modulation (PAM)
(c) Pulse Position Modulation (PPM)
(d) Pulse Width Modulation (PWM)
Show Answer & Explanation

Answer: (a) Pulse Code Modulation (PCM)

Explanation:
1. PCM is the standard scheme for digital transmission.

Teacher's Note:
1. Recall the basic fact.

Question 24: Communication is the process of
(a) keeping in touch
(b) exchange of information
(c) broad casting
(d) entertainment by electronics
Show Answer & Explanation

Answer: (b) exchange of information

Explanation:
1. Communication means the exchange of information between a sender and a receiver.

Teacher's Note:
1. Recall the basic fact.

Question 25: Consider telecommunication through optical fibres. Which of the following statements is/are correct? I. Optical fibres may have homogeneous core with a suitable cladding. II. Optical fibres can be of graded refractive index. III. Optical fibres are subject to electromagnetic interference from outside. IV. Optical fibres have extremely low transmission loss.
(a) I and II
(b) I and III
(c) I, II and IV
(d) I, II, III and IV
Show Answer & Explanation

Answer: (c) I, II and IV

Explanation:
1. Optical fibres are immune to electromagnetic interference, so III is false.

Teacher's Note:
1. Recall the basic fact.

Free study material for Physics

Practice MCQs for JEE Physics Communication System

JEE Physics Communication System Objective Test Questions

Test your conceptual understanding of Communication System with these targeted multiple-choice questions. Designed in alignment with the latest JEE curriculum for JEE Physics, these problem sets build accuracy and prepare students for objective exams.

NCERT-Aligned Objective Questions and Solutions

Each question includes structured solution keys mapped directly to standard JEE textbooks, helping students evaluate their reasoning and correct mistakes early in their revision.

Next Steps in Your Exam Preparation

Explore our broader library of printable assignments, chapter notes, and mock tests designed to support continuous revision and secure higher marks in JEE assessments.

FAQs

Where can I access latest JEE Physics Communication System MCQs Set 09?

You can get most exhaustive JEE Physics Communication System MCQs Set 09 for free on StudiesToday.com. These MCQs for JEE Physics are updated for the 2026-27 academic session as per JEE examination standards.

Are Assertion-Reasoning and Case-Study MCQs included in the Physics JEE material?

Yes, our JEE Physics Communication System MCQs Set 09 include the latest type of questions, such as Assertion-Reasoning and Case-based MCQs. 50% of the JEE paper is now competency-based.

How do practicing Physics MCQs help in scoring full marks in JEE exams?

By solving our JEE Physics Communication System MCQs Set 09, JEE students can improve their accuracy and speed which is important as objective questions provide a chance to secure 100% marks in the Physics.

Do you provide answers and explanations for JEE Physics Communication System MCQs Set 09?

Yes, Physics MCQs for JEE have answer key and brief explanations to help students understand logic behind the correct option as its important for 2026 competency-focused JEE exams.

Can I practice these Physics JEE MCQs online?

Yes, you can also access online interactive tests for JEE Physics Communication System MCQs Set 09 on StudiesToday.com as they provide instant answers and score to help you track your progress in Physics.