The difference between charges that are accelerating and those that are not lies in their ability to produce electromagnetic waves (EMW). When charges are accelerated, meaning their speed or direction changes, they generate electromagnetic waves. On the other hand, charges that are not accelerating, i.e., moving at a constant velocity or at rest, do not produce EMW.
According to Maxwell's equations, which describe the behavior of electric and magnetic fields, changing electric fields generate magnetic fields, and changing magnetic fields generate electric fields. This mutual generation of electric and magnetic fields results in the propagation of electromagnetic waves through space.
When charges are accelerated, their motion causes a change in electric fields, and this changing electric field gives rise to a magnetic field. The changing magnetic field, in turn, generates a new electric field, and this process continues as a self-sustaining wave. These electromagnetic waves carry energy and information, and they propagate outward from the source at the speed of light.
The production of electromagnetic waves by accelerating charges is a fundamental principle of electromagnetism. It is the basis for various technological applications, such as radio waves, microwaves, visible light, X-rays, and gamma rays. In these cases, the acceleration of charges occurs in various ways, such as oscillating currents in antennas, transitions of electrons in atoms, or the movement of charged particles in accelerators.
In contrast, when charges are not accelerating, there is no changing electric or magnetic field associated with their motion. Consequently, no electromagnetic waves are produced. This is why stationary or uniformly moving charges do not emit EMW.
In summary, the key distinction between charges that are accelerating and those that are not lies in their ability to generate electromagnetic waves. Accelerated charges produce changing electric and magnetic fields, leading to the emission of EMW, while charges at rest or moving uniformly do not generate EMW because there is no changing field associated with their motion.