Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Electromagnetic Emissions

Description

This lecture covers the emission of electromagnetic waves from accelerated charges, including the calculation of Poynting flux, Larmor's formula, and electrostatic forces. It also discusses the relationship between charge, mass, and acceleration.

In MOOC

The Radio Sky I: Science and Observations

Official source

Related concepts (25)

Electrostatics

Electrostatics is a branch of physics that studies slow-moving or stationary electric charges. Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber, ἤλεκτρον (), was thus the source of the word 'electricity'. Electrostatic phenomena arise from the forces that electric charges exert on each other. Such forces are described by Coulomb's law.

Poynting vector

In physics, the Poynting vector (or Umov–Poynting vector) represents the directional energy flux (the energy transfer per unit area per unit time) or power flow of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m2); kg/s3 in base SI units. It is named after its discoverer John Henry Poynting who first derived it in 1884. Nikolay Umov is also credited with formulating the concept.

Coulomb's law

Coulomb's inverse-square law, or simply Coulomb's law, is an experimental law of physics that calculates the amount of force between two electrically charged particles at rest. This electric force is conventionally called electrostatic force or Coulomb force. Although the law was known earlier, it was first published in 1785 by French physicist Charles-Augustin de Coulomb, hence the name. Coulomb's law was essential to the development of the theory of electromagnetism and maybe even its starting point, as it allowed meaningful discussions of the amount of electric charge in a particle.

Electric field

An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges and time-varying electric currents. Electric fields and magnetic fields are both manifestations of the electromagnetic field, one of the four fundamental interactions (also called forces) of nature.

Larmor formula

In electrodynamics, the Larmor formula is used to calculate the total power radiated by a nonrelativistic point charge as it accelerates. It was first derived by J. J. Larmor in 1897, in the context of the wave theory of light. When any charged particle (such as an electron, a proton, or an ion) accelerates, energy is radiated in the form of electromagnetic waves. For a particle whose velocity is small relative to the speed of light (i.e.

Related lectures (46)

Electromagnetic waves

Explores the wave equation for electromagnetic fields, the propagation of electromagnetic waves, the fundamental velocity of light, and the concept of polarization.

Laser Fundamentals: Principles and Applications for Engineers

Covers the fundamentals of lasers, their historical development, and applications in engineering fields.

Electromagnetic Phenomena

Introduces the importance of studying electromagnetic phenomena and Maxwell's equations.

Electromagnetic Waves: Energy Density and Poynting Vector

Explains the energy density and Poynting vector in electromagnetic waves.

Cosmological Puzzles: Dark Matter and Energy