# Communication Systems MCQ Questions for Class 12 Physics Chapter 15 with Answers

Find here the NCERT chapter-wise Multiple Choice Questions from Class 12 Physics book Chapter 15 Communication Systems with Answers Pdf free download. This may assist you to understand and check your knowledge about the chapters. Students also can take a free test of the Multiple Choice Questions of Communication Systems. Each question has four options followed by the right answer. These MCQ Questions are selected supported by the newest exam pattern as announced by CBSE.

## Q1. The wavelength of a wave of frequency 10 kHz is:

(i) 30 m
(ii) 300 m
(iii) 30 km
(iv) 300 km

(iii) 30 km

(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

(iii) 3.7 to 4.2 GHz

(i) 3
(ii) 2
(iii) 4
(iv) 7

(i) 3

## Q4. 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

(ii) the frequency range allocated to a given source

## Q5. 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

(ii) 20 Hz to 20 kHz

## Q6. 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

(i) 0.05 and 1 ± 0.010 MHz

## Q7. Which of the following is the purpose of the transmitter?

(i) Converts signals to electric form
(iii) Converting the signal into a suitable form
(iv) Reduces noise from signals

(iii) Converting the signal into a suitable form

## Q8. 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

(iv) 54 – 72 MHz

## Q9. 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

(iv) remote sensing

(i) 8 kHz
(ii) 4 kHz
(iii) 7.6 kHz
(iv) 3.8 kHz
(e) 400 kHz

(i) 8 kHz

## Q11. Which among the following can be an input to a transmitter?

(i) Voice signal
(ii) Electric signal
(iii) Light signal
(iv) Wave signal

(ii) Electric signal

## Q12. 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

(iv) modulated wave

## Q13. 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

(i) Leonov 1965

(i) 1280 m
(ii) 1125 m
(iii) 1560 m
(iv) 79 m

(ii) 1125 m

## Q15. 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

(iv) Channel imperfection

## Q16. Which of the following is drawback of amplitude modulation?

(i) low efficiency
(ii) noise reception
(iii) operating range is small
(iv) all of these

(iv) all of these

(i) Loudspeaker
(ii) Amplifier
(iii) Microphone
(iv) All

(ii) Amplifier

## Q18. 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

(iv) 800 – 950 MHz

## Q19.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

(iii) Operating on the received signal

## Q20. 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

(iii) modulation is doubled

(i) MF
(ii) HUF
(iii) VHF
(iv) UHF

(iv) UHF

## Q22. The waves that are bent down by the ionosphere are

(i) ground waves
(ii) surface waves
(iii) sky waves
(iv) space waves

(iii) sky waves

## Q23. Find the odd one out.

(ii) Telephone
(iii) Television
(iv) Computer networking

Ab(ii) Telephoneve

## Q24. 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.

(iv) repeater stations are used.

## Q25. An antenna is:

(i) Inductive
(ii) Capacitive
(iii) Resistive
(iv) A transformer

(i) Inductive

(iii) television
(iv) telephony

(iv) telephony

## Q27. 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

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

## Q28. The modulation index in amplitude modulation is:

(i) Always zero
(ii) Between 0 and 1
(iii) Between 1 and ∞
(iv) None of these

(iii) Between 1 and ∞

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