These notes for CBSE Class 12 Physics, Chapter 5, focus on Magnetism and Matter, specifically detailing electromagnetic waves. It explains that electromagnetic waves are disturbances in space caused by varying electric and magnetic fields, perpendicular to each other and to the direction of propagation. These waves do not require a medium and travel at the speed of light in free space. The notes highlight key properties, including their transverse nature, generation by oscillating charges, and the ability to exhibit superposition and polarization. It also touches upon conduction and displacement currents, noting their continuity and the distinct origins of each: conduction current from electron flow and displacement current from changing electric flux. These concepts are crucial for understanding the fundamental nature of electromagnetic waves and their behavior, aiding students in their exam preparation.
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• Conduction current and displacement current together have the property of continuity.Conduction current & displacement current are precisely the same.
• Conduction current arises due to flow of electrons in the conductor. Displacement current arises due to electric flux changing with time.
• Displacement current:
The variation of electric and magnetic fields, perpendicular to each other, producing electromagnetic disturbance in space at right angles to each other, which have properties of waves and propagate through free space without any materialistic medium is called electromagnetic wave.
• Properties of electromagnetic waves:
E M Waves are transverse in nature.
They are produced by oscillating or accelerating charged particles.
They do not require any medium for their propagation.
They obey principle of superposition.
They show polarization effect.
Electric field is only responsible for optical effects of EM waves.
The amplitude of electric & magnetic fields are related by In free space they travel with the speed c =
Electromagnetic waves are disturbances in space caused by varying electric and magnetic fields, propagating at right angles to each other and to their direction of motion without needing a medium.
Electromagnetic waves are transverse in nature, meaning the oscillations are perpendicular to the direction of wave propagation.
They are produced by oscillating or accelerating charged particles.
No, electromagnetic waves do not require any medium for their propagation and can travel through free space.
Conduction current arises from the flow of electrons in a conductor, while displacement current arises from a change in electric flux over time. They are considered the same in terms of continuity.
In free space, electromagnetic waves travel with the speed of light, denoted as c.
Key properties include being transverse, produced by accelerating charges, not needing a medium, obeying the principle of superposition, and showing polarization.
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