Revision Notes for Class 12 Physics Chapter 15 - Communication Systems - Free PDF Download
FAQs on Communication Systems Class 12 Notes CBSE Physics Chapter 15 (Free PDF Download)
1. How to top in the CBSE Board Exam?
It is possible to secure top marks in the CBSE board exam. Students must follow a precise plan. Students appearing in the 12th board exam have to give their best on every subject and cover the syllabus within the perfect time.
Also, they must be clear about the perceptions of exact subjects like Physics, Chemistry, Mathematics, and other subjects. The continuous practice of mock tests and previous year question papers will also help the students.
2. What Do You Mean by Point-to-Point Communication?
When communication takes place between two endpoints, it is called point-to-point communication. Telephones are the best example of point-to-point communication. You can talk at one end, and the listener can hear your voice at the other end.
3. Write a Short Note About Wireless Networks?
Nowadays, many devices like laptops, mobiles, tablets, etc. are operational and dependable on wireless networking. The wireless networks help to transmit data between multiple devices. These networks are using the electromagnetic waves which are described by Maxwell equations.
4. Write Some Basic Advantages of Digital Communication?
There is no noise, interference, and distortion available in digital signals. These signals are not being affected by the above factors. We can rely on digital circuits, and they are easy to design with a very low price-point.
5. How are electromagnetic waves transmitted over long distances?
When radio waves are transmitted over long distances, a transmitter relays the electromagnetic signal which travels through space and reaches the receiving antenna at the other end. As the signal moves away from the transmitter the signal strength reduces which is impacted by several factors such as the composition of the earth's atmosphere. To reduce the signal strength loss, different techniques are used such as using antennas of a specific wavelength.
6. What are the three modes of electromagnetic wave propagation?
There are three modes of EM wave propagation -
Surface Wave Propagation - In this, the wave glides over the earth’s surface. In this mode, the antennas are large and located close to the ground surface to reduce the loss of signal strength.
Skywave Propagation - In this mode, the propagation is achieved by the ionospheric reflection of the radio waves towards the earth.
Space Wave Propagation - In this mode, a space wave travels in a straight line from the transmitter to the receiver antenna.
7. What is modulation and its types?
The low-frequency waves cannot be transmitted over long distances, therefore they are superimposed over a wave of the high energy carrier signal by the process called modulation. Three different types of modulations can be done to the amplitude, frequency and phase of the carrier signal according to the message signal. These are -
Amplitude modulation (AM)
Frequency modulation (FM)
Phase modulation (PM)
Learn more about this in the Class 12 Physics Chapter 15 Revision Notes on Vedantu.
8. What are the elements of a communication system?
There are three basic elements of a communication system -
Transmitter - The transmitter converts the signal produced by the information source into a form that can be transmitted through a suitable channel.
Transmission Channel - It is the medium through which the signal passes between the transmitter and the receiver.
Receiver - The receiver decodes the message signal from the signals received at the channel output.
This concept is talked about in detail in the Class 12 Physics Chapter 15 Revision Notes.To revise the chapter students can download the revision notes free of cost from the vedantu website (vedantu.com).
9. What is amplitude modulation and how is it detected?
Amplitude modulation is a process by which the amplitude of the carrier signal is modified according to the message signal to carry it over long distances. AM waves can be produced by applying the carrier and message signal to a non-linear device followed by a band pass filter. AM detection is the process by which the modulating signal is recovered from the modulated carrier waveform. This is done using a rectifier and an envelope detector.