Wireless Communication 12th Science Online Test
Wireless Communication 12th Science Online Test
Quiz-summary
0 of 60 questions completed
Questions:
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
Information
Tnpsc Online Test
You have already completed the quiz before. Hence you can not start it again.
Quiz is loading...
You must sign in or sign up to start the quiz.
You have to finish following quiz, to start this quiz:
Results
0 of 60 questions answered correctly
Your time:
Time has elapsed
You have reached 0 of 0 points, (0)
Average score |
|
Your score |
|
Categories
- Not categorized 0%
Pos. | Name | Entered on | Points | Result |
---|---|---|---|---|
Table is loading | ||||
No data available | ||||
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
- Answered
- Review
-
Question 1 of 60
1. Question
Which of the following statement is correct?
1) The communication industry is one of the largest in size and is the oldest
2) Right from the developments made in communication by great scientists like J.C. Bose, G. Marconi, and Alexander Graham Bell, communication has witnessed leaps and boundsCorrect
Communication exists since the dawn of life in this world. Growth in science and technology removed the locational disadvantage effectively. Information can be exchanged from one person to another anywhere on this Earth. Right from the developments made in communication by great scientists like J.C. Bose, G. Marconi, and Alexander Graham Bell, communication has witnessed leaps and bounds. The communication industry is one of the largest in size and is the oldest since communication through telegraph (1844), telephone (1876), and Radio (1887) started centuries back.
Incorrect
Communication exists since the dawn of life in this world. Growth in science and technology removed the locational disadvantage effectively. Information can be exchanged from one person to another anywhere on this Earth. Right from the developments made in communication by great scientists like J.C. Bose, G. Marconi, and Alexander Graham Bell, communication has witnessed leaps and bounds. The communication industry is one of the largest in size and is the oldest since communication through telegraph (1844), telephone (1876), and Radio (1887) started centuries back.
-
Question 2 of 60
2. Question
Which century witnessed a leap over the development of communication?
Correct
The intensive research in the mid- and late nineteenth century leads to the development of long-distance transmission in the shortest possible time. However, the 20th century witnessed a leap over the development of communication, meeting the demands of speed and secured transfer of data.
Incorrect
The intensive research in the mid- and late nineteenth century leads to the development of long-distance transmission in the shortest possible time. However, the 20th century witnessed a leap over the development of communication, meeting the demands of speed and secured transfer of data.
-
Question 3 of 60
3. Question
Which of the following is audio frequency?
Correct
The transmission of information through short distances does not require complicated techniques. The energy of the information signal is sufficient enough to be sent directly. However, if the information, for example, audio frequency (20 to 20,000 Hz) needs to be transmitted to long distances across the world, certain techniques are required to transmit the information without any loss.
Incorrect
The transmission of information through short distances does not require complicated techniques. The energy of the information signal is sufficient enough to be sent directly. However, if the information, for example, audio frequency (20 to 20,000 Hz) needs to be transmitted to long distances across the world, certain techniques are required to transmit the information without any loss.
-
Question 4 of 60
4. Question
Carrier signal is a________
Correct
For long distance transmission, the low frequency baseband signal (input signal) is superimposed onto a high frequency radio signal by a process called modulation. In the modulation process, a very high frequency signal called carrier signal (radio signal) is used to carry the baseband signal.
Incorrect
For long distance transmission, the low frequency baseband signal (input signal) is superimposed onto a high frequency radio signal by a process called modulation. In the modulation process, a very high frequency signal called carrier signal (radio signal) is used to carry the baseband signal.
-
Question 5 of 60
5. Question
The carrier signal is usually a______ wave
Correct
The carrier signal is usually a sine wave signal. In the modulation process, a very high frequency signal called carrier signal (radio signal) is used to carry the baseband signal.
Incorrect
The carrier signal is usually a sine wave signal. In the modulation process, a very high frequency signal called carrier signal (radio signal) is used to carry the baseband signal.
-
Question 6 of 60
6. Question
Which of the following statement is correct?
1) As the frequency of the carrier signal is very high, it can be transmitted to long distances with less attenuation.
2) Carrier signal does not have information.
3) The carrier signal will be more compatible with the communication medium like free space and can propagate with greater efficiency.Correct
As the frequency of the carrier signal is very high, it can be transmitted to long distances with less attenuation. The carrier signal is usually a sine wave signal. Also, the carrier signal will be more compatible with the communication medium like free space and can propagate with greater efficiency. Carrier signal does not have information.
Incorrect
As the frequency of the carrier signal is very high, it can be transmitted to long distances with less attenuation. The carrier signal is usually a sine wave signal. Also, the carrier signal will be more compatible with the communication medium like free space and can propagate with greater efficiency. Carrier signal does not have information.
-
Question 7 of 60
7. Question
ec = Ec sin (2πνc t + ϕ), What does Ec mean?
Correct
A sinusoidal carrier wave can be represented as ec = Ec sin (2πνc t + ϕ), where Ec is the amplitude, νc is the frequency and ϕ is the initial phase of the carrier wave at any instant of time t.
Incorrect
A sinusoidal carrier wave can be represented as ec = Ec sin (2πνc t + ϕ), where Ec is the amplitude, νc is the frequency and ϕ is the initial phase of the carrier wave at any instant of time t.
-
Question 8 of 60
8. Question
Which of the following parameters of carrier signal can be modified?
1) Amplitude
2) Phase
3) FrequencyCorrect
Three characteristics in the carrier signal can be modified by the baseband signal during the process of modulation: amplitude, frequency and phase of the carrier signal.
Incorrect
Three characteristics in the carrier signal can be modified by the baseband signal during the process of modulation: amplitude, frequency and phase of the carrier signal.
-
Question 9 of 60
9. Question
How many types of many types of modulation are there based on modification parameters?
Correct
There are 3 types of modulation based on which parameter is modified. They are (i) amplitude modulation, (ii) frequency modulation and (iii) phase modulation.
Incorrect
There are 3 types of modulation based on which parameter is modified. They are (i) amplitude modulation, (ii) frequency modulation and (iii) phase modulation.
-
Question 10 of 60
10. Question
Which of the following statement is correct?
1) If the amplitude of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal, then it is called amplitude modulation
2) Here the frequency and the phase of the carrier signal remain constant
3) Amplitude modulation is used in radio, mobile and TV broadcastingCorrect
If the amplitude of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal, then it is called amplitude modulation. Here the frequency and the phase of the carrier signal remain constant. Amplitude modulation is used in radio and TV broadcasting.
Incorrect
If the amplitude of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal, then it is called amplitude modulation. Here the frequency and the phase of the carrier signal remain constant. Amplitude modulation is used in radio and TV broadcasting.
-
Question 11 of 60
11. Question
Which of the following are advantage of AM?
Correct
Advantages of AM
i) Easy transmission and reception
ii) Lesser bandwidth requirements
iii) Low cost
Limitations of AM
i) Noise level is high
ii) Low efficiency
iii) Small operating rangeIncorrect
Advantages of AM
i) Easy transmission and reception
ii) Lesser bandwidth requirements
iii) Low cost
Limitations of AM
i) Noise level is high
ii) Low efficiency
iii) Small operating range -
Question 12 of 60
12. Question
Which of the following statement is correct about Frequency modulation?
1) The frequency of the baseband signal is modified in proportion to the instantaneous amplitude of the carrier signal
2) Increase in the amplitude of the baseband signal increases the frequency of the carrier signal and vice versa
3) The amplitude and the phase of the carrier signal remain constant.Correct
The frequency of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal in frequency modulation. Here the amplitude and the phase of the carrier signal remain constant. Increase in the amplitude of the baseband signal increases the frequency of the carrier signal and vice versa.
Incorrect
The frequency of the carrier signal is modified in proportion to the instantaneous amplitude of the baseband signal in frequency modulation. Here the amplitude and the phase of the carrier signal remain constant. Increase in the amplitude of the baseband signal increases the frequency of the carrier signal and vice versa.
-
Question 13 of 60
13. Question
Louder signal leads to______ and relatively weaker signals to____
Correct
Increase in the amplitude of the baseband signal increases the frequency of the carrier signal and vice versa. This leads to compressions and rarefactions in the frequency spectrum of the modulated wave. Louder signal leads to compressions and relatively weaker signals to rarefactions.
Incorrect
Increase in the amplitude of the baseband signal increases the frequency of the carrier signal and vice versa. This leads to compressions and rarefactions in the frequency spectrum of the modulated wave. Louder signal leads to compressions and relatively weaker signals to rarefactions.
-
Question 14 of 60
14. Question
Which of the following statement is correct?
1) When the frequency of the baseband signal is zero (no input signal), there is no change in the frequency of the carrier wave
2) It is at its normal frequency and is called as centre frequency or resting frequency
3) Practically this is the allotted frequency of the FM transmitterCorrect
When the frequency of the baseband signal is zero (no input signal), there is no change in the frequency of the carrier wave. It is at its normal frequency and is called as centre frequency or resting frequency. Practically this is the allotted frequency of the FM transmitter.
Incorrect
When the frequency of the baseband signal is zero (no input signal), there is no change in the frequency of the carrier wave. It is at its normal frequency and is called as centre frequency or resting frequency. Practically this is the allotted frequency of the FM transmitter.
-
Question 15 of 60
15. Question
Which of the following are advantages of FM?
1) Decreased signal to noise ratio
2) FM bandwidth covers the entire frequency range which humans can hear
3) The operating range is quite largeCorrect
Advantages of FM
i) Large decrease in noise. This leads to an increase in signal-noise ratio.
ii) The operating range is quite large.
iii) The transmission efficiency is very high as all the transmitted power is useful.
iv) FM bandwidth covers the entire frequency range which humans can hear. Due to this, FM radio has better quality compared to AM radio.Incorrect
Advantages of FM
i) Large decrease in noise. This leads to an increase in signal-noise ratio.
ii) The operating range is quite large.
iii) The transmission efficiency is very high as all the transmitted power is useful.
iv) FM bandwidth covers the entire frequency range which humans can hear. Due to this, FM radio has better quality compared to AM radio. -
Question 16 of 60
16. Question
Which of the following statement is correct?
1) In phase modulation, the instantaneous amplitude of the baseband signal modifies the phase of the carrier signal keeping the amplitude and frequency constant
2) This modulation is used to generate frequency modulated signals
3) It is similar to frequency modulation except that the phase of the carrier is varied instead of varying frequencyCorrect
In phase modulation, the instantaneous amplitude of the baseband signal modifies the phase of the carrier signal keeping the amplitude and frequency constant. This modulation is used to generate frequency modulated signals. It is similar to frequency modulation except that the phase of the carrier is varied instead of varying frequency.
Incorrect
In phase modulation, the instantaneous amplitude of the baseband signal modifies the phase of the carrier signal keeping the amplitude and frequency constant. This modulation is used to generate frequency modulated signals. It is similar to frequency modulation except that the phase of the carrier is varied instead of varying frequency.
-
Question 17 of 60
17. Question
Which of the following statement is correct?
1) If a square wave is used as the baseband signal, then phase reversal takes place in the modulated signal
2) FM and PM waves are same as square wave modulating signalCorrect
If a square wave is used as the baseband signal, then phase reversal takes place in the modulated signal. FM and PM waves are completely different for square wave modulating signal.
Incorrect
If a square wave is used as the baseband signal, then phase reversal takes place in the modulated signal. FM and PM waves are completely different for square wave modulating signal.
-
Question 18 of 60
18. Question
The frequency shift in phase modulation depends on____
1) Amplitude of the carrier signal
2) Amplitude of the modulating signal
3) The frequency of the signalCorrect
The frequency shift in carrier wave frequency exists in phase modulation as well. The frequency shift depends on (i) amplitude of the modulating signal and (ii) the frequency of the signal.
Incorrect
The frequency shift in carrier wave frequency exists in phase modulation as well. The frequency shift depends on (i) amplitude of the modulating signal and (ii) the frequency of the signal.
-
Question 19 of 60
19. Question
Which of the following statement is correct?
1) PM wave is similar to FM wave
2) PM generally uses a larger bandwidth than FM
3) Phase modulation provides high transmission speed on a given bandwidthCorrect
PM wave is similar to FM wave. PM generally uses a smaller bandwidth than FM. In other words, in PM, more information can be sent in a given bandwidth. Hence, phase modulation provides high transmission speed on a given bandwidth.
Incorrect
PM wave is similar to FM wave. PM generally uses a smaller bandwidth than FM. In other words, in PM, more information can be sent in a given bandwidth. Hence, phase modulation provides high transmission speed on a given bandwidth.
-
Question 20 of 60
20. Question
Which of the following statement is correct?
1) Electronics plays a major role in communication
2) Electronic communication is nothing but the transmission of sound, text, pictures, or data through a medium
3) Long distance transmission uses free space as a mediumCorrect
Electronics plays a major role in communication. Electronic communication is nothing but the transmission of sound, text, pictures, or data through a medium. Long distance transmission uses free space as a medium. This section provides sufficient information on how voice signal is transmitted by a transmitter through space and received by the receiver at the receiving end.
Incorrect
Electronics plays a major role in communication. Electronic communication is nothing but the transmission of sound, text, pictures, or data through a medium. Long distance transmission uses free space as a medium. This section provides sufficient information on how voice signal is transmitted by a transmitter through space and received by the receiver at the receiving end.
-
Question 21 of 60
21. Question
Which of the following could be input to the input transducer?
1) Image
2) Music
3) SpeechCorrect
Information can be in the form of speech, music, pictures, or computer data. This information is given as input to the input transducer.
Incorrect
Information can be in the form of speech, music, pictures, or computer data. This information is given as input to the input transducer.
-
Question 22 of 60
22. Question
____ is a device that converts variations in a physical quantity into an equivalent electrical signal
or vice versaCorrect
A transducer is a device that converts variations in a physical quantity (pressure, temperature, sound) into an equivalent electrical signal or vice versa.
Incorrect
A transducer is a device that converts variations in a physical quantity (pressure, temperature, sound) into an equivalent electrical signal or vice versa.
-
Question 23 of 60
23. Question
The electrical equivalent of the original information is called________
Correct
The electrical equivalent of the original information is called the baseband signal. The best example for the transducer is the microphone that converts sound energy into electrical energy
Incorrect
The electrical equivalent of the original information is called the baseband signal. The best example for the transducer is the microphone that converts sound energy into electrical energy
-
Question 24 of 60
24. Question
Which of the following circuits are included in transmitter?
1) Amplifier
2) Modulator
3) Power amplifierCorrect
Transmitter feeds the electrical signal from the transducer to the communication channel. It consists of circuits such as amplifier, oscillator, modulator and power amplifier. The transmitter is located at the broadcasting station.
Incorrect
Transmitter feeds the electrical signal from the transducer to the communication channel. It consists of circuits such as amplifier, oscillator, modulator and power amplifier. The transmitter is located at the broadcasting station.
-
Question 25 of 60
25. Question
Which of the following statement is correct?
1) The transducer output is very weak and is amplified by the amplifier.
2) Oscillator generates high-frequency carrier wave (a sinusoidal wave) for long distance transmission into spaceCorrect
Amplifier: The transducer output is very weak and is amplified by the amplifier.
Oscillator: It generates high-frequency carrier wave (a sinusoidal wave) for long distance transmission into space. As the energy of a wave is proportional to its frequency, the carrier wave has very high energy.Incorrect
Amplifier: The transducer output is very weak and is amplified by the amplifier.
Oscillator: It generates high-frequency carrier wave (a sinusoidal wave) for long distance transmission into space. As the energy of a wave is proportional to its frequency, the carrier wave has very high energy. -
Question 26 of 60
26. Question
_________ superimposes the baseband signal onto the carrier signal
Correct
Modulator superimposes the baseband signal onto the carrier signal and generates the modulated signal.
Incorrect
Modulator superimposes the baseband signal onto the carrier signal and generates the modulated signal.
-
Question 27 of 60
27. Question
What is the velocity of Electromagnetic waves?
Correct
Transmitting antenna radiates the radio signal into space in all directions. It travels in the form of electromagnetic waves with the velocity of light (3 × 108 m s–1)
Incorrect
Transmitting antenna radiates the radio signal into space in all directions. It travels in the form of electromagnetic waves with the velocity of light (3 × 108 m s–1)
-
Question 28 of 60
28. Question
Which of the following statement is correct?
1) Communication channel is used to carry the electrical signal from transmitter to receiver with less noise or distortion
2) The communication medium is basically of two types: wireline communication and wireless communicationCorrect
Communication channel is used to carry the electrical signal from transmitter to receiver with less noise or distortion. The communication medium is basically of two types: wireline communication and wireless communication.
Incorrect
Communication channel is used to carry the electrical signal from transmitter to receiver with less noise or distortion. The communication medium is basically of two types: wireline communication and wireless communication.
-
Question 29 of 60
29. Question
Which of the following are used in wireline connection?
Correct
Wireline communication (point to point communication) uses mediums like wires, cables and optical fibres. These systems cannot be used for long distance transmission as they are connected physically. Examples are telephone, intercom and cable TV.
Incorrect
Wireline communication (point to point communication) uses mediums like wires, cables and optical fibres. These systems cannot be used for long distance transmission as they are connected physically. Examples are telephone, intercom and cable TV.
-
Question 30 of 60
30. Question
Which of the following statement is correct?
1) Wireless communication uses free space as a communication medium
2) The signals are transmitted in the form of electromagnetic waves with the help of a transmitting antenna
3) Mobile, radio or TV broadcasting and satellite communication are examples of wireless communicationCorrect
Wireless communication uses free space as a communication medium. The signals are transmitted in the form of electromagnetic waves with the help of a transmitting antenna. Hence wireless communication is used for long distance transmission. Examples are mobile, radio or TV broadcasting and satellite communication.
Incorrect
Wireless communication uses free space as a communication medium. The signals are transmitted in the form of electromagnetic waves with the help of a transmitting antenna. Hence wireless communication is used for long distance transmission. Examples are mobile, radio or TV broadcasting and satellite communication.
-
Question 31 of 60
31. Question
Which of the following statement about noise is correct?
1) It is the undesirable electrical signal that interferes with the transmitted signal.
2) Noise can be completely eliminated
3) Noise attenuates or reduces the quality of the transmitted signal.Correct
Noise is the undesirable electrical signal that interferes with the transmitted signal. Noise attenuates or reduces the quality of the transmitted signal. Noise cannot be completely eliminated. However, it can be reduced using various techniques.
Incorrect
Noise is the undesirable electrical signal that interferes with the transmitted signal. Noise attenuates or reduces the quality of the transmitted signal. Noise cannot be completely eliminated. However, it can be reduced using various techniques.
-
Question 32 of 60
32. Question
Which of the following are man-made noise disturbance?
1) Radiation from Sun
2) Automobiles
3) Electric motorCorrect
Noise may be man-made (automobiles, welding machines, electric motors etc.) or natural (lightning, radiation from sun and stars and environmental effects).
Incorrect
Noise may be man-made (automobiles, welding machines, electric motors etc.) or natural (lightning, radiation from sun and stars and environmental effects).
-
Question 33 of 60
33. Question
Which of the following statement is correct?
1) The signals that are transmitted through the communication medium are received by a receiving antenna which converts EM waves into RF signals and are fed into the receiver.
2) The receiver consists of electronic circuits like demodulator, amplifier, detector etc.Correct
The signals that are transmitted through the communication medium are received by a receiving antenna which converts EM waves into RF signals and are fed into the receiver. The receiver consists of electronic circuits like demodulator, amplifier, detector etc. The demodulator extracts the baseband signal from the modulated signal. Then the baseband signal is detected and amplified using amplifiers. Finally, it is fed to the output transducer.
Incorrect
The signals that are transmitted through the communication medium are received by a receiving antenna which converts EM waves into RF signals and are fed into the receiver. The receiver consists of electronic circuits like demodulator, amplifier, detector etc. The demodulator extracts the baseband signal from the modulated signal. Then the baseband signal is detected and amplified using amplifiers. Finally, it is fed to the output transducer.
-
Question 34 of 60
34. Question
Which of the following statement is incorrect?
1) Repeaters are used to increase the range or distance through which the signals are sent
2) The signals are received, amplified and retransmitted with a carrier signal of different frequency to the destinationCorrect
Repeaters are used to increase the range or distance through which the signals are sent. It is a combination of transmitter and receiver. The signals are received, amplified and retransmitted with a carrier signal of different frequency to the destination. The best example is the communication satellite in space
Incorrect
Repeaters are used to increase the range or distance through which the signals are sent. It is a combination of transmitter and receiver. The signals are received, amplified and retransmitted with a carrier signal of different frequency to the destination. The best example is the communication satellite in space
-
Question 35 of 60
35. Question
Which of the following are output transducer?
1) Speakers
2) Picture tubes
3) Microphone
4) Computer monitorCorrect
Output transducer converts the electrical signal back to its original form such as sound, music, pictures or data. Examples of output transducers are loudspeakers, picture tubes, computer monitor, etc.
Incorrect
Output transducer converts the electrical signal back to its original form such as sound, music, pictures or data. Examples of output transducers are loudspeakers, picture tubes, computer monitor, etc.
-
Question 36 of 60
36. Question
The loss of strength of a signal while propagating through a medium is known as_______
Correct
The loss of strength of a signal while propagating through a medium is known as attenuation. Range is the maximum distance between the source and the destination up to which the signal is received with sufficient strength.
Incorrect
The loss of strength of a signal while propagating through a medium is known as attenuation. Range is the maximum distance between the source and the destination up to which the signal is received with sufficient strength.
-
Question 37 of 60
37. Question
Which of the following can be transmitted through bandwidth of signal?
1) Voice
2) Music
3) PictureCorrect
The frequency range over which the baseband signals or the information signals such as voice, music, picture etc is transmitted is known as bandwidth. Each of these signals has different frequencies.
Incorrect
The frequency range over which the baseband signals or the information signals such as voice, music, picture etc is transmitted is known as bandwidth. Each of these signals has different frequencies.
-
Question 38 of 60
38. Question
Bandwidth gives the difference between the____ and____ frequency limits of the signal
Correct
The type of communication system depends on the nature of the frequency band for a given signal. Bandwidth gives the difference between the upper and lower frequency limits of the signal.
Incorrect
The type of communication system depends on the nature of the frequency band for a given signal. Bandwidth gives the difference between the upper and lower frequency limits of the signal.
-
Question 39 of 60
39. Question
The height of the antenna must be a multiple of_____
Correct
Antenna is used at both transmitter and receiver end. Antenna height is an important parameter to be discussed. The height of the antenna must be a multiple of h = λ/ 4
Incorrect
Antenna is used at both transmitter and receiver end. Antenna height is an important parameter to be discussed. The height of the antenna must be a multiple of h = λ/ 4
-
Question 40 of 60
40. Question
The frequencies from___ kHz to____ GHz are transmitted through wireless communication
Correct
The information signal modulated with the carrier wave (radio wave) is transmitted by an antenna. This travels through space and is received by the receiving antenna at the other end. The frequencies from 2 kHz to 400 GHz are transmitted through wireless communication.
Incorrect
The information signal modulated with the carrier wave (radio wave) is transmitted by an antenna. This travels through space and is received by the receiving antenna at the other end. The frequencies from 2 kHz to 400 GHz are transmitted through wireless communication.
-
Question 41 of 60
41. Question
Match the following
I. Ground wave propagation 1. 30 MHz to 400 GHz
II. Sky wave propagation 2. 2 kHz to 2 MHz
III. Space wave propagation 3. 3 MHz to 30 MHzCorrect
• Ground wave propagation (or) surface wave propagation (nearly 2 kHz to 2 MHz)
• Sky wave propagation (or) ionospheric propagation (nearly 3 MHz to 30 MHz)
• Space wave propagation (nearly 30 MHz to 400 GHz)Incorrect
• Ground wave propagation (or) surface wave propagation (nearly 2 kHz to 2 MHz)
• Sky wave propagation (or) ionospheric propagation (nearly 3 MHz to 30 MHz)
• Space wave propagation (nearly 30 MHz to 400 GHz) -
Question 42 of 60
42. Question
Which of the following statement is correct?
1) If the electromagnetic waves transmitted by the transmitter glide over the surface of the earth to reach the receiver, then the propagation is called ground wave propagation
2) Both transmitting and receiving antennas must be close to the earthCorrect
If the electromagnetic waves transmitted by the transmitter glide over the surface of the earth to reach the receiver, then the propagation is called ground wave propagation. The corresponding waves are called ground waves or surface waves. Both transmitting and receiving antennas must be close to the earth. The size of the antenna plays a major role in deciding the efficiency of the radiation of signals.
Incorrect
If the electromagnetic waves transmitted by the transmitter glide over the surface of the earth to reach the receiver, then the propagation is called ground wave propagation. The corresponding waves are called ground waves or surface waves. Both transmitting and receiving antennas must be close to the earth. The size of the antenna plays a major role in deciding the efficiency of the radiation of signals.
-
Question 43 of 60
43. Question
The attenuation of the signal with distance depends on_____
1) Frequency of the transmitter
2) Power of the transmitter
3) Condition of the earth surfaceCorrect
The attenuation of the signal with distance depends on (i) power of the transmitter (ii) frequency of the transmitter and (iii) condition of the Earth surface.
Incorrect
The attenuation of the signal with distance depends on (i) power of the transmitter (ii) frequency of the transmitter and (iii) condition of the Earth surface.
-
Question 44 of 60
44. Question
The earth behaves like a leaky_____
Correct
When the transmitted signal in the form of EM wave is in contact with the Earth, it induces charges in the Earth and constitutes a current. Due to this, the Earth behaves like a leaky capacitor which leads to the attenuation of the wave.
Incorrect
When the transmitted signal in the form of EM wave is in contact with the Earth, it induces charges in the Earth and constitutes a current. Due to this, the Earth behaves like a leaky capacitor which leads to the attenuation of the wave.
-
Question 45 of 60
45. Question
The frequency of the ground waves is mostly less than____ MHz
Correct
The frequency of the ground waves is mostly less than 2 MHz as high frequency waves undergo more absorption of energy at the earth’s atmosphere.
Incorrect
The frequency of the ground waves is mostly less than 2 MHz as high frequency waves undergo more absorption of energy at the earth’s atmosphere.
-
Question 46 of 60
46. Question
Surface wave propagation is used in____
Correct
The medium wave signals received during the day time use surface wave propagation. It is mainly used in local broadcasting, radio navigation, for ship-to-ship, ship to-shore communication and mobile communication.
Incorrect
The medium wave signals received during the day time use surface wave propagation. It is mainly used in local broadcasting, radio navigation, for ship-to-ship, ship to-shore communication and mobile communication.
-
Question 47 of 60
47. Question
Which of the following statement is incorrect?
1) The mode of propagation in which the electromagnetic waves radiated from an antenna, directed upwards at large angles, gets reflected by the troposphere back to earth is called ionospheric propagation
2) The corresponding waves are called sky wavesCorrect
The mode of propagation in which the electromagnetic waves radiated from an antenna, directed upwards at large angles, gets reflected by the ionosphere back to earth is called sky wave propagation or ionospheric propagation. The corresponding waves are called sky waves.
Incorrect
The mode of propagation in which the electromagnetic waves radiated from an antenna, directed upwards at large angles, gets reflected by the ionosphere back to earth is called sky wave propagation or ionospheric propagation. The corresponding waves are called sky waves.
-
Question 48 of 60
48. Question
A single reflection helps the radio waves to travel a distance of approximately_____ Km
Correct
Extremely long-distance communication is also possible as the radio waves can undergo multiple reflections between the earth and the ionosphere. A single reflection helps the radio waves to travel a distance of approximately 4000 km.
Incorrect
Extremely long-distance communication is also possible as the radio waves can undergo multiple reflections between the earth and the ionosphere. A single reflection helps the radio waves to travel a distance of approximately 4000 km.
-
Question 49 of 60
49. Question
Ionosphere distance of approximately____ km and spreads up to____ km above the Earth surface
Correct
Ionosphere acts as a reflecting surface. It is at a distance of approximately 50 km and spreads up to 400 km above the Earth surface. Due to the absorption of ultraviolet rays, cosmic ray, and other high energy radiations like α, β rays from sun, the air molecules in the ionosphere get ionized.
Incorrect
Ionosphere acts as a reflecting surface. It is at a distance of approximately 50 km and spreads up to 400 km above the Earth surface. Due to the absorption of ultraviolet rays, cosmic ray, and other high energy radiations like α, β rays from sun, the air molecules in the ionosphere get ionized.
-
Question 50 of 60
50. Question
The phenomenon of bending the radio waves back to earth is_____
Correct
Due to the absorption of ultraviolet rays, cosmic ray, and other high energy radiations like α, β rays from sun, the air molecules in the ionosphere get ionized. This produces charged ions and these ions provide a reflecting medium for the reflection of radio waves or communication waves back to Earth within the permitted frequency range. The phenomenon of bending the radio waves back to earth is nothing but the total internal reflection.
Incorrect
Due to the absorption of ultraviolet rays, cosmic ray, and other high energy radiations like α, β rays from sun, the air molecules in the ionosphere get ionized. This produces charged ions and these ions provide a reflecting medium for the reflection of radio waves or communication waves back to Earth within the permitted frequency range. The phenomenon of bending the radio waves back to earth is nothing but the total internal reflection.
-
Question 51 of 60
51. Question
The shortest distance between the transmitter and the point of reception of the sky wave along the
surface is called____Correct
The shortest distance between the transmitter and the point of reception of the sky wave along the surface is called as the skip distance.
Incorrect
The shortest distance between the transmitter and the point of reception of the sky wave along the surface is called as the skip distance.
-
Question 52 of 60
52. Question
Lesser the frequency, skip distance is_____
Correct
The higher the frequency, higher is the skip distance and for a frequency less than the critical frequency, skip distance is zero.
Incorrect
The higher the frequency, higher is the skip distance and for a frequency less than the critical frequency, skip distance is zero.
-
Question 53 of 60
53. Question
The electromagnetic waves of very high frequencies above___ MHz are called as space waves.
Correct
The process of sending and receiving information signal through space is called space wave communication. The electromagnetic waves of very high frequencies above 30 MHz are called as space waves.
Incorrect
The process of sending and receiving information signal through space is called space wave communication. The electromagnetic waves of very high frequencies above 30 MHz are called as space waves.
-
Question 54 of 60
54. Question
Which of the following are the advantages of microwaves over radio waves?
1) High data rate
2) Larger bandwidth
3) Better directivity
4) Large antenna sizeCorrect
Microwaves having high frequencies (super high frequency band) are used against radio waves due to certain advantages: larger bandwidth, high data rates, better directivity, small antenna size, low power consumption, etc.
Incorrect
Microwaves having high frequencies (super high frequency band) are used against radio waves due to certain advantages: larger bandwidth, high data rates, better directivity, small antenna size, low power consumption, etc.
-
Question 55 of 60
55. Question
What is the radius of earth?
Correct
The range or distance (d) of coverage of the propagation depends on the height (h) of the antenna given by the equation, where R is the radius of the Earth and it is 6400 km.
Incorrect
The range or distance (d) of coverage of the propagation depends on the height (h) of the antenna given by the equation, where R is the radius of the Earth and it is 6400 km.
-
Question 56 of 60
56. Question
A transmitting antenna has a height of 40 m and the height of the receiving antenna is 30 m. What
is the maximum distance between them for line-of-sight communication? The radius of the earth is 6.4×106 m.Correct
Incorrect
-
Question 57 of 60
57. Question
Which of the following are advantages of fibre cables?
1) Fiber cables are very thin and weigh lesser than copper cable
2) Fiber optic system is immune to electrical interferences
3) Fiber optic cables are cheaper than copper cablesCorrect
Merits
i) Fiber cables are very thin and weigh lesser than copper cables. ii) This system has much larger band width. This means that its information carrying capacity is larger. iii) Fiber optic system is immune to electrical interferences. iv) Fiber optic cables are cheaper than copper cables.Incorrect
Merits
i) Fiber cables are very thin and weigh lesser than copper cables. ii) This system has much larger band width. This means that its information carrying capacity is larger. iii) Fiber optic system is immune to electrical interferences. iv) Fiber optic cables are cheaper than copper cables. -
Question 58 of 60
58. Question
Recent developments in optical communication provide the data speed at the rate of __ Gbps
Correct
Fiber optic cables provide the fastest transmission rate compared to any other form of transmission. It can provide data speed of 1 Gbps for homes and business. Multimode fibers operate at the speed of 10 Mbps. Recent developments in optical communication provide the data speed at the rate of 25 Gbps
Incorrect
Fiber optic cables provide the fastest transmission rate compared to any other form of transmission. It can provide data speed of 1 Gbps for homes and business. Multimode fibers operate at the speed of 10 Mbps. Recent developments in optical communication provide the data speed at the rate of 25 Gbps
-
Question 59 of 60
59. Question
Which of the following statement is correct?
1) The satellite communication is a mode of communication of signal between transmitter and receiver via satellite
2) The message signal from the Earth station is transmitted to the satellite on board via an uplinkCorrect
The satellite communication is a mode of communication of signal between transmitter and receiver via satellite. The message signal from the Earth station is transmitted to the satellite on board via an uplink (frequency band 6 GHz), amplified by a transponder and then retransmitted to another Earth station via a downlink (frequency band 4 GHz)
Incorrect
The satellite communication is a mode of communication of signal between transmitter and receiver via satellite. The message signal from the Earth station is transmitted to the satellite on board via an uplink (frequency band 6 GHz), amplified by a transponder and then retransmitted to another Earth station via a downlink (frequency band 4 GHz)
-
Question 60 of 60
60. Question
Which of the following are technology in mobile communication?
Correct
Recently, the mobile communication technology has evolved through various stages like 2G, 3G, 4G, 5G, WiMAX, Wibro, EDGE, GPRS and many others. This helps to increase the speed of communication and the range of coverage. The connectivity issues have decreased with reliable and secure connections. The GPS (Global Positioning System) and GSM (Global System for Mobile communication) technology play an important role in mobile communication. This increases the utilization of bandwidth of the network, sharing of the networks, error detections, etc. Many methods like digital switching, TDMA, CDMA have been used to ease the communication process.
Incorrect
Recently, the mobile communication technology has evolved through various stages like 2G, 3G, 4G, 5G, WiMAX, Wibro, EDGE, GPRS and many others. This helps to increase the speed of communication and the range of coverage. The connectivity issues have decreased with reliable and secure connections. The GPS (Global Positioning System) and GSM (Global System for Mobile communication) technology play an important role in mobile communication. This increases the utilization of bandwidth of the network, sharing of the networks, error detections, etc. Many methods like digital switching, TDMA, CDMA have been used to ease the communication process.
Leaderboard: Wireless Communication 12th Science Online Test
Pos. | Name | Entered on | Points | Result |
---|---|---|---|---|
Table is loading | ||||
No data available | ||||