Check the below NCERT MCQ Questions for Class 12 Physics Chapter 15 Communication Systems with Answers Pdf free download. MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. We have provided Communication Systems Class 12 Physics MCQs Questions with Answers to help students understand the concept very well.

Communication Systems Class 12 MCQs Questions with Answers

Question 1.
Who undertook the first space walk and in which year?
(a) Leonov 1965
(b) Neil Armstrong, 1969
(c) Rakesh Sharma. 1998
(d) None of these

Answer

Answer: (a) Leonov 1965


Question 2.
The term used “to collect the information about an object and a place without physical contact” is called :
(a) modulation
(b) communication
(c) amplification
(d) remote sensing

Answer

Answer: (d) remote sensing


Question 3.
The velocity of electromagnetic wave is:
(a) 3 × 105 ms-1
(b) 3 × 106 ms-1
(c) 3 × 108 ms-1
(d) 3 × 1010 ms-1

Answer

Answer: (c) 3 × 108 ms-1


Question 4.
The audio frequencies range from:
(a) 20 Hz to 20.000 kHz
(b) 20 Hz to 20 kHz
(c) 20 kHz to 20.000 kHz
(d) None of these

Answer

Answer: (b) 20 Hz to 20 kHz


Question 5.
The wavelength of a wave of frequency 10 kHz is:
(a) 30 m
(b) 300 m
(c) 30 km
(d) 300 km

Answer

Answer: (c) 30 km


Question 6.
The area served by an antenna of height 100 m is:
(a) 109
(b) 4 × 109
(c) 6 × 109
(d) 8 × 1010

Answer

Answer: (b) 4 × 109


Question 7.
Which of the following is not transducer?
(a) Loudspeaker
(b) Amplifier
(c) Microphone
(d) All

Answer

Answer: (b) Amplifier


Question 8.
The space waves which are affected seriously by atmospheric conditions are:
(a) MF
(b) HUF
(c) VHF
(d) UHF

Answer

Answer: (d) UHF


Question 9.
An antenna is:
(a) Inductive
(b) Capacitive
(c) Resistive
(d) A transformer

Answer

Answer: (a) Inductive


Question 10.
Broadcasting antenna are generally:
(a) Ommi directional type
(b) Vertical type
(c) Horizontal type
(d) None

Answer

Answer: (b) Vertical type


Question 11.
The modulation index in amplitude modulation is:
(a) Always zero
(b) Between 0 and 1
(c) Between 1 and ∞
(d) None of these

Answer

Answer: (c) Between 1 and ∞


Question 12.
The output of a digital computer is an example of:
(a) digital signal
(b) analog signal
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer

Answer: (a) digital signal


Question 13.
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
(c) Leonov, 1965
(d) None of these

Answer

Answer: (a) Neil Armstrong, 1969


Question 14.
A microphone converts:
(a) sound signals into electrical signals
(b) electrical signals into sound signals
(c) both (a) and (b)
(d) Neither (a) nor (b)

Answer

Answer: (a) sound signals into electrical signals


Question 15.
A loudspeaker converts:
(a) electrical signals into sound signals
(b) sound signals into electrical signals
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer

Answer: (a) electrical signals into sound signals


Question 16.
The sound produced by a tuning fork is a sort of:
(a) analog signal
(b) digital signal
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer

Answer: (a) analog signal


Question 17.
The length of a half wave dipole at 30 mega-hertz is:
(a) 5 m
(b) 10 m
(c) 25 m
(d) 80 m

Answer

Answer: (a) 5 m


Question 18.
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 electro-magnetic waves
(d) by superimposing it on damped electro-magnetic waves

Answer

Answer: (c) by superimposing it on undamped electro-magnetic waves


Question 19.
The output of a digital computer is an example of:
(a) digital signal
(b) analog signal
(c) both (a) and (b) above
(d) neither (a) nor (b)

Answer

Answer: (a) digital signal


Question 20.
Which is more advantageous?
(a) analog data communication
(b) digital data communication
(c) both (a) and (b) are equally good
(d) depends on the situation

Answer

Answer: (b) digital data communication


Question 21.
Communication channel consists of:
(a) transmission line only
(b) optical fibre only
(c) free space only
(d) All of the above

Answer

Answer: (d) All of the above


Question 22.
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
(c) its use avoids receiver complexity
(d) No other modulation system can provide the necessary bandwidth faithful transmission

Answer

Answer: (c) its use avoids receiver complexity


Question 23.
Digital signals:
(a) represents values as discrete steps
(b) Do not represents values as discrete steps
(c) represent values steps
(d) represent random steps

Answer

Answer: (a) represents values as discrete steps


Question 24.
Digital signals:
(a) deal with all sort of values
(b) can use decimal system
(c) can use binary system
(d) (b) and (c) both

Answer

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


Question 25.
Increase in frequency deviation results into:
(a) increase in noise of FM receiver
(b) decrease in noise of AM receiver
(c) increase in noise of Am receiver
(d) decrease in noise of FM receiver

Answer

Answer: (b) decrease in noise of AM receiver


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