Definitions [2]
Definition: Electromagnetic Waves
Electromagnetic waves are self-propagating transverse waves consisting of oscillating electric and magnetic fields that do not require a medium for propagation.
Definition: Electromagnetic Spectrum
The whole range of frequencies/wavelengths of electromagnetic waves arranged in ascending or descending order is known as the electromagnetic spectrum.
Key Points
Key Points: Electromagnetic Waves
- EM waves are transverse
- E ⟂ B ⟂ direction of propagation
- E and B are in phase
- Speed:
\[c=\frac{1}{\sqrt{\mu_0\varepsilon_0}}=3\times10^8\mathrm{m/s}\] - Poynting Vector:
\[\vec{S}=\frac{\vec{E}\times\vec{B}}{\mu_{0}}\] -
Intensity:
\[I=\frac{1}{2}c\varepsilon_0E_0^2\]
Key Points:
- Electric and magnetic fields in an electromagnetic wave are perpendicular to each other.
- Both fields are perpendicular to the direction of propagation.
- Electromagnetic waves are self-sustaining oscillations in a vacuum.
- No material medium is required for their propagation.
- In a vacuum, their speed is 3 × 108 m/s.
- In a material medium, velocity is \[\frac {1}{\sqrt {με}}\].
- Radio, TV signals, and light are important examples of energy transfer by electromagnetic waves.
Concepts [3]
- Introduction to Electromagnetic Waves
- Types of Spectrum Emission and Absorption Spectrumfraunhofer Lines
- Nature of Electromagnetic Waves
