Grade 10
  1. Mechanics  1.1. Dynamics  1.1.1. Motion in one dimension  1.1.2. Motion in two dimensions  1.1.3. Displacement and Distance  1.1.4. Speed and Velocity  1.1.5. Acceleration  1.1.6. Graphical representation of motion  1.1.7. Equations of motion  1.1.8. Free fall and acceleration due to gravity  1.1.9. Projectile motion  1.1.10. Relative speed  1.2. Dynamics  1.2.1. Newton's Laws of Motion  1.2.2. Inertia and mass  1.2.3. Force and its types  1.2.4. action and reaction force  1.2.5. Friction and its effects  1.2.6. Coefficient of friction  1.2.7. Circular motion  1.2.8. Centripetal force and centripetal acceleration  1.2.9. Momentum and Impulse  1.2.10. Conservation of momentum  1.2.11. Newton's third law and applications  1.3. Work, Energy and Power  1.3.1. Work done by the force  1.3.2. Work–energy theorem  1.3.3. Kinetic energy  1.3.4. Potential energy  1.3.5. Mechanical energy  1.3.6. Energy Conservation  1.3.7. Power and efficiency  1.3.8. Renewable and non-renewable energy sources  1.4. Gravitational force  1.4.1. Newton's law of universal gravitation  1.4.2. Gravitational field and field strength  1.4.3. Acceleration due to gravity on different planets  1.4.4. Kepler's laws of planetary motion  1.4.5. Orbits and satellites  1.4.6. Weight and apparent weight  1.4.7. Gravitational potential energy
  2. Properties of matter  2.1. States of matter  2.1.1. Solid, liquid and gas  2.1.2. Molecular structure of matter  2.1.3. Intermolecular forces  2.1.4. Plasma and Bose–Einstein condensate  2.2. Pressure  2.2.1. Definition of Pressure  2.2.2. Pressure in liquids  2.2.3. Atmospheric pressure  2.2.4. Pascal's principle  2.2.5. Archimedes' Principle and Buoyancy  2.2.6. Surface tension and capillarity  2.3. Elasticity  2.3.1. Hooke's law  2.3.2. Stress and strain  2.3.3. Elastic Limit and Modulus of Elasticity  2.3.4. Applications of Elasticity
  3. Thermal physics  3.1. heat and temperature  3.1.1. Difference Between Heat and Temperature  3.1.2. Temperature scale  3.1.3. Thermal expansion  3.1.4. Thermal equilibrium  3.2. Heat transfer  3.2.1. Conductivity  3.2.2. Convection  3.2.3. Radiation  3.2.4. Insulation and its applications  3.3. Thermal properties of matter  3.3.1. Specific heat capacity  3.3.2. Latent heat and phase change  3.3.3. Boiling and Melting Point  3.3.4. Heat engines and refrigeration  3.4. Laws of Thermodynamics  3.4.1. Zeroth law of thermodynamics  3.4.2. First law of thermodynamics  3.4.3. Second law of thermodynamics  3.4.4. Carnot cycle
  4. Waves and optics  4.1. Nature and properties of waves  4.1.1. Types of waves in nature and properties of waves  4.1.2. Transverse and longitudinal waves  4.1.3. Wave parameters  4.1.4. Reflection and refraction of waves  4.1.5. Superposition and Interference  4.1.6. Standing Waves and Resonance  4.1.7. Doppler effect  4.2. Sound waves  4.2.1. Characteristics of sound waves  4.2.2. Speed of sound in different mediums  4.2.3. Applications of sound waves  4.2.4. Ultrasound and its uses  4.3. Light Waves and Optics  4.3.1. Nature of light  4.3.2. Reflection of light  4.3.3. Laws of reflection  4.3.4. Mirrors and Image Formation  4.3.5. Refraction of light  4.3.6. Snell's Law  4.3.7. Lenses and Image Formation  4.3.8. Total internal reflection and critical angle  4.3.9. Optical fibre  4.4. Optical Instruments  4.4.1. Microscope  4.4.2. Telescope  4.4.3. Human eye and vision defects  4.4.4. Camera and its working principle
  5. Electricity and Magnetism  5.1. Electrostatics  5.1.1. Electric charge and its properties  5.1.2. Conductors and Insulators  5.1.3. Coulomb's law  5.1.4. Electric field and field lines  5.1.5. Electric potential and potential difference  5.1.6. Capacitors and Capacitance  5.2. Current Electricity  5.2.1. Electric current and its measurement  5.2.2. Ohm's law  5.2.3. Resistance and resistivity  5.2.4. Series and Parallel Circuits  5.2.5. Electric power and energy  5.2.6. Kirchhoff's Laws  5.3. Magnetism and Electromagnetism  5.3.1. Magnetic field and field lines  5.3.2. Magnetic effects of electric current  5.3.3. Electromagnetic induction  5.3.4. Faraday's laws of electromagnetic induction  5.3.5. Transformers and Applications  5.3.6. AC and DC current
  6. Modern Physics  6.1. Nuclear physics  6.1.1. Structure of the atom  6.1.2. Bohr's atomic model  6.1.3. Electron Energy Levels  6.1.4. X-rays and applications  6.2. Radioactivity  6.2.1. Types of radiation  6.2.2. Half-life and radioactive decay  6.2.3. Nuclear reactions and applications  6.2.4. Fission and Fusion  6.3. Quantum physics  6.3.1. Wave–particle duality  6.3.2. Photoelectric effect  6.3.3. Energy quantization  6.3.4. Heisenberg's uncertainty principle
  7. Electronics and Communication  7.1. Semiconductors  7.1.1. Conductors, Insulators and Semiconductors  7.1.2. Diodes and their applications  7.1.3. Transistors and Logic Gates  7.1.4. LEDs and photodiodes  7.2. Communication Systems  7.2.1. Basics of communication  7.2.2. Analog and digital signals  7.2.3. Wireless and optical fibre communication  7.2.4. Radio Waves and Modulation

Grade 10 → Electronics and Communication → Communication Systems ↓


Radio Waves and Modulation


Introduction

In the world of electronics and communications, radio waves and modulation are important concepts. They play a huge role in enabling devices to communicate over long distances. In this explanation, we'll dive into the fascinating world of radio waves and see how modulation helps transmit information.

Understanding radio waves

Radio waves are part of the electromagnetic spectrum, just like visible light, microwaves, and X-rays. They have the longest wavelengths in the electromagnetic spectrum, ranging from about one millimeter to 100 kilometers, and their frequencies range from about 3 kHz to 300 GHz.

These waves are used to transmit information over distances by changing some properties of the wave.

wavelength of radio waves

In the figure above, the 'peaks' and 'troughs' of the wave represent its wavelength. The distance between two peaks or two troughs is the wavelength.

Properties of radio waves

Radio waves have several properties:

  • Frequency (f): The number of times a wave oscillates in one second. Measured in Hertz (Hz).
  • Wavelength (λ): The distance between successive crests of a wave. It is inversely proportional to frequency.
  • Amplitude: The height of the wave, which determines its strength or intensity.
  • Speed of light (c): Radio waves travel at the speed of light, which is about 3 × 10 8 m/s.

The relationship between the frequency, wavelength, and speed of light is given by this equation:

c = f × λ

Modulation

Modulation is the process of making changes to a carrier wave in order to transmit information. The carrier wave is a stationary wave that is modulated to encode the information being sent.

Mainly two types of modulation are used in communication systems:

  • Amplitude modulation (AM)
  • Frequency modulation (FM)

Amplitude modulation (AM)

In amplitude modulation, the amplitude of the carrier wave varies in proportion to the message signal. This means that the height of the wave increases or decreases depending on the information being sent.

Amplitude Modulation

This is common in traditional AM radio broadcasting. However, it has some drawbacks, as it is more sensitive to noise interference than other modulation techniques.

Frequency modulation (FM)

In frequency modulation, the frequency of the carrier wave varies with the message signal. This means that the distance between the waves changes depending on the information being sent.

Frequency Modulation

FM is widely used in FM radio broadcasting and is less susceptible to interference, giving it better sound quality than AM.

Applications of radio waves and modulation

Radio waves and modulation techniques are used in a variety of communications systems, including:

  • Radio broadcasting: AM and FM radios use modulation to send audio information through the air.
  • Television broadcasting: Television signals use radio waves to transmit audio and video content.
  • Mobile communications: Cell phones use complex modulation techniques for voice and data transmission.
  • Satellite communications: Satellites use radio waves to send and receive information around the world.

Closing thoughts

Understanding radio waves and modulation is vital to understanding how modern communication systems work. These concepts form the backbone of various technologies that have become an integral part of daily life. By learning these principles, students can gain a deeper understanding for the technology used every day.

In a world increasingly dependent on wireless communications, knowledge of radio waves and modulation is invaluable. These concepts not only power today's technology, but also pave the way for future innovations.


Grade 10 → 7.2.4


U
username
0%
completed in Grade 10

← Prev (7.2.3)
Wireless and optical fibre communication

Comments 



Radio Waves and Modulation

https://www.physicsflow.com/g10/7.2.4?pfal=en