# Class 12 Physics MCQs Communication Systems for JEE/NEET

Here, you will get Class 12 Physics MCQ of Chapter 15 Communication Systems for cracking JEE and NEET/AIIMS. By solving these MCQs of Class 12 Physics Chapter 15 Communication Systems, you will get the confidence to crack JEE or NEET. Practice MCQ Questions for Class 12 Physics with Answers on a daily basis and score well in exams.

## Communication Systems Class 12 MCQs Questions with Answers

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

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: (b) 20 Hz to 20 kHz

The area served by an antenna of height 100 m is
(a) 109
(b) 4 × 109 m²
(c) 6 × 109
(d) 8 × 1010

Answer: (b) 4 × 109 m²

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

(a) Ommi directional type
(b) Vertical type
(c) Horizontal type
(d) None

In amplitude modulation
(a) the amplitude of the carrier remains constant.
(b) the amplitude of the carrier varies in accordance with the amplitude of the modulating signal.
(c) the amplitude of carrier varies in accordance with the frequency of the modulating signal.
(d) None of these.

Answer: (b) the amplitude of the carrier varies in accordance with the amplitude of the modulating signal

For television transmission, the frequency employed is normally in the range
(a) 30-300 Hz
(b) 30-300 kHz
(c) 30-300 MHz
(d) 30-300 GHz

Which one of the following can happen to the electromagnetic waves travelling in free space
(a) Reflection
(b) Refraction
(c) absorption
(d) attenuation

An antenna is
(a) capacitive
(b) reactive
(c) inductive above its resonance frequency.
(d) None of these

Answer: (c) inductive above its resonance frequency

Optical communication uses the frequency range of
(a) 109 to 1010 Hz
(b) 105 to 106 Hz
(c) 1014 to 1015 Hz
(d) 1016 to 1017 Hz

Answer: (c) 1014 to 1015 Hz

The numbers of geostationary satellites needed for uninterrupted global coverage is
(a) 3
(b) 4
(c) 2
(d) 1

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

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)

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

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

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

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

Answer: (c) Between 1 and ∞

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

The information bearing signal is called
(a) Base band signal
(b) digital signal
(c) Analog signal
(d) None of these

In a single reflection from the ionosphere, the sky waves cover a distance on ground not more than
(a) 400 m
(b) 4,000 m
(c) 400 km
(d) 4,000 km

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

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

Answer: (d) All of the above

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: (a) represents values as discrete steps

(a) analog data communication
(b) digital data communication
(c) both (a) and (b) are equally good
(d) depends on the situation