Communication Systems
- Which frequency range is used for TV transmission ?
(A) 30 HZ – 300 Hz
(B) 30 KHZ – 300 kHZ
(C) 30 MHz – 300 MHz
(D) 30 GHz – 300 GHZ
Answer : (C) 30 MHz – 300 MHz
- Sky wave communication is based upon :
(A) reflection by ionosphere
(B) absorption by ionosphere
(C) transmission through ionosphere
(D) none of these
Answer : (A) reflection by ionosphere
- The loss of strength of a signal while propagating though a medium is known as :
(A) reception
(B) absorption
(C) transmission
(D) attenuation
Answer : (D) attenuation
- The process of increasing the strength of a signal using an electronic circuit is called :
(A) amplification
(B) modulation
(C) demodulation
(D) transmission
Answer : (A) amplification
- Modem is a device which performs :
(A) modulation
(B) demodulation
(C) rectification
(D) modulation and demodulation
Answer : (D) modulation and demodulation
- The mode of propagation used by short wave broadcast services is :
(A) space wave
(B) sky wave
(C) ground wave
(D) both ‘A’ and ‘C’
Answer : (B) sky wave
- Large bandwidth for higher data rate is achieved by using :
(A) high frequency carrier wave
(B) high frequency audio wave
(C) low frequency carrier wave
(D) low frequency audio wave
Answer : (A) high frequency carrier wave
- Who invented world wide web?
(A) J.C.R. Licklider
(B) Tim Berners-Lee
(C) Alexander Graham Bell
(D) Samuel F.B. Morse
Answer : (B) Tim Berners-Lee
- The device which is a combination of a receiver and a transmitter is :
(A) Amplifier
(B) Repeater
(C) Transducer
(D) Modulator
Answer : (B) Repeater
- Which of the following is not a transducer ?
(A) Loudspeaker
(B) Amplifier
(C) Microphone
(D) All of these
Answer : (B) Amplifier
- Which of the following is an example of broadcast mode of communication?
(A) Radio
(B) Television
(C) Mobile
(D) Both A and B
Answer : (D) Both A and B
- The waves that are bent down by the ionosphere are:
(A) ground waves
(B) surface waves
(C) space waves
(D) sky waves
Answer : (D) sky waves
- 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 : (A) Leonov, 1965
- 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 : (D) remote sensing
- The velocity of electromagnetic wave is :
(A) 3 x 109 ms-1
(B) 3 x 106 ms-1
(C) 3 x 108 ms-1
(D) 3 x 1010 ms-1
Answer : (C) 3 x 108 ms-1
- From which layer of atmosphere are radio waves reflected ?
(A) Ionosphere
(B) Mesosphere
(C) Chromosphere
(D) None of the above
Answer : (A) Ionosphere
- The modulation index in amplitude modulation :
(A) is always zero
(B) lies between 0 and 1
(C) lies between 1 and
(D) can never exceed 0.5
Answer : (B) lies between 0 and 1
- 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 : (A) digital signal
- Basically, a communication system is a :
(A) transmitter
(B) receiver
(C) messenger
(D) All of these
Answer : (D) All of these
- Present day communication systems are :
(A) electrical only
(B) electronic only
(C) optical only
(D) All of the above
Answer : (D) All of the above
- Major parts of a communication system are :
(A) transmitter and receiver
(B) receiver and communication channel
(C) transmitter and communication channel
(D) transmitter, receiver and communication channel
Answer : (D) transmitter, receiver and communication channel
- Frequencies in the UHF range normally propagate by means of :
(A) Ground wave
(B) Sky waves
(C) Surface wave
(D) Space wave
Answer : (D) Space wave
- The height of a TV transmission tower at any place on the surface of the earth is 245m. The maximum distance up to which transmission of tower will reach is :
(A) 245 m
(B) 245 km
(C) 56 km
(D) 112 km
Answer : (C) 56 km
- Modulation is of:
(A) 2 types
(B) 3 types
(C) 4 types
(D) 5 types
Answer : (B) 3 types
- Meaning of ‘FAX’ is :
(A) Full Access Transmission
(B) Fascimile Telegraphy
(C) Factual Auto Access
(D) Feed Auto Exchange
Answer : (B) Fascimile Telegraphy
