Electrons emit radiation when they undergo acceleration or deceleration. This phenomenon is known as electromagnetic radiation or simply radiation. It occurs due to the fundamental properties of electric charge and the interaction between electrons and electromagnetic fields.
When an electron accelerates or changes its velocity, its motion creates a changing electric field around it. According to Maxwell's equations, a changing electric field induces a magnetic field, and a changing magnetic field induces an electric field. These changing electric and magnetic fields propagate through space as electromagnetic waves, which are a form of radiation.
The emission of radiation by electrons is governed by the laws of electrodynamics. When an electron accelerates, it emits radiation, losing energy in the process. This radiation can have various forms depending on the characteristics of the acceleration and the resulting electromagnetic waves.
For example, when an electron in an atom transitions from a higher energy level to a lower energy level, it undergoes acceleration. As a result, the electron emits a photon, which is a discrete packet of electromagnetic energy. This emission is responsible for phenomena like the emission of light by excited atoms or the operation of lasers.
Similarly, when electrons move through a conductor or are accelerated in vacuum tubes, they emit radiation in the form of radio waves, microwaves, or even X-rays, depending on the specific conditions and energy levels involved.
It's important to note that electrons continuously undergo random thermal motion, resulting in some level of acceleration and emission of radiation, albeit at low levels. However, significant radiation emission typically occurs when electrons undergo accelerated motion or are subjected to external forces.
Overall, the emission of radiation by electrons is a fundamental aspect of electromagnetism, and it arises from the interaction between charged particles and electromagnetic fields.