Electromagnetism
One of four fundamental forces governing atomic and molecular interactions.
Electromagnetism is a fundamental interaction in physics that occurs between particles with electric charge via electromagnetic fields. It is one of the four fundamental forces of nature and is the dominant force in the interactions of atoms and molecules, describing the intertwined phenomena of electricity, magnetism, and optics.
- field
- Physics
- known_for
- Unifying electricity, magnetism, and optics; describing electromagnetic waves; fundamental force
- sub-disciplines
- Electrostatics, magnetostatics, electrodynamics
Lore & Background
Electromagnetism has been studied since ancient times to explain lightning, static electricity, and the attraction of magnetized iron ore and compasses. In the 18th and 19th centuries, scientists developed mathematical relationships between these phenomena and electric charges and currents, showing that electrical and magnetic phenomena were related and could create self-sustaining electromagnetic waves, including visible light and other forms of electromagnetic radiation such as gamma-rays, x-rays, ultraviolet, infrared, microwaves, and radio waves.
Reader's Guide
Electromagnetism is the second strongest of the four known fundamental forces and has unlimited range. It is responsible for many chemical and physical phenomena observed in daily life, including holding atoms together via electrostatic attraction between nuclei and electrons, and allowing atoms to combine into molecules. Magnetic interactions between electron spin and angular momentum also play a role in chemical reactivity, studied in spin chemistry. The theory of electromagnetism has been refined to account for quantum mechanics and relativity; its implications helped inspire Einstein's theory of special relativity in 1905. Quantum electrodynamics (QED) modifies Maxwell's equations to be consistent with the quantized nature of matter, expressing changes in the electromagnetic field as discrete excitations called photons. Electromagnetism also plays crucial roles in modern technology, including electrical energy production, light and sound production, fiber optic and wireless communication, sensors, computation, and mechanical motors.
Did You Know?
- The electromagnetic force is the second strongest of the four known fundamental forces and has unlimited range.
- At high energy, the weak force and electromagnetic force are unified as a single interaction called the electroweak interaction.
- Electromagnetic waves include gamma-rays, x-rays, ultraviolet, visible light, infrared radiation, microwaves, and radio waves.
- Quantum electrodynamics (QED) expresses changes in the electromagnetic field as discrete excitations called photons.
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