In Physics, communication means the transmission of information. This chapter does not have many concepts and the problems asked in the examination also does not have many varieties. Candidates who are preparing this chapter should focus on gaining the knowledge of basic concepts, formula, and bandwidth of signals. Also, you should have a clear idea about the functions of all the equipment.
Quick Links:
For the transmission of information from one place to another, there are various essential elements of communication that are all discussed in this article. The solved examples will help you in getting a clear idea about the basic concepts of the communication system for JEE Main.
Must Read:
Transmitter: Transmitter is used to transmit the input signal from the information source.
Channel: Channel is defined as the medium through which the signal is sent from transmitter to receiver.
Receiver: The receiver is used to extract the designed message signal from the received signal at the channel output.
Question: An antenna is a device that
Solution: (3)
Check Gujarat Board Released Question Banks for JEE Main
The difference between the maximum and minimum frequency of a signal is known as the bandwidth of that signal.
The frequency band of some important wireless communications
Service | Frequency Bands |
---|---|
Standard AM Broadcast | 540 to 1600 KHz |
FM Broadcast | 88 to 108 MHz |
Television (VHF) | 54 to 72 MHz |
TV | 76 to 88 MHz |
VMF | 174 to 216 MHz |
Cellular Mobile Radio | 896 to 901 MHz 840 to 935 MHz |
Satellite communication | 5.925 to 6.425 MHz 3.7 to 4.2 GHz |
Question: Which mode of communication is not employed for the transmission of T.V. signals?
Solution: (1)
Ground Wave Propagation: The radio waves that travel through the atmosphere following the surface of the earth are known as ground waves or surface waves. And their propagation is called as ground wave propagation or surface wave propagation.
Important points to Remember
SkyWave Propagation: The sky waves are radio waves that have a frequency between 2 MHz to 30 MHz.
Important points to Remember
Space Wave Propagation: These are high-frequency radio waves.
Important Points to Remember
Question: Modulation is the process of superposing
Solution: (1)
Download JEE Main Practice Paper
It is the process by which input signal or modulating signal is mounted onto another signal of a high frequency which is called the carrier signal. The resultant signal is called a modulated signal.
Amplitude modulation: In this modulation, the amplitude of the carrier is varied according to the information signals.
Let represent carrier wave and represents the message or the modulating signal where is the angular frequency of the message signal.
The modulated signal can be represented as
Moducation Index can be represented by
Frequency Modulation: When the frequency of the carrier wave is changed with the change in the intensity of the modulating signal it is called frequency modulation.
Moducation Factor or Index and Carrier Swing (CS) can be defined as
Moducation Factor, m = Maximum frequency deviation/ Modulating Frequency = , where
Also,
1. Question: A laser beam used for carrying out surgery because it is
Solution: (1)
2. Question: The range of skywave propagation is suitable for radio- waves of frequency
Solution: (3)
3. Question: Let us consider that a T.V. tower has a height of 150 m. Ff the total population covered is 50 lakh then what is the population density around the T.V. tower? The radius of the earth is 6.4×106m.
Solution: (2)
4 Question: If an FM radio receiver is tuned to 98.6 MHz broadcast station then what will be the image frequency?
Solution: (3)
5 Question: What is the phenomenon by which light travels in an optical fiber?
Solution: (3)
*The article might have information for the previous academic years, please refer the official website of the exam.