Yes, when an electron accelerates or changes its velocity, it emits electromagnetic radiation in the form of an electromagnetic wave. This process is known as bremsstrahlung or braking radiation.
According to classical electromagnetic theory, an accelerating charged particle, such as an electron, generates changing electric and magnetic fields in its surroundings. These changing fields propagate as electromagnetic waves, carrying energy away from the accelerating particle.
The emitted electromagnetic radiation can have a wide range of frequencies, including radio waves, microwaves, visible light, X-rays, and even gamma rays, depending on the characteristics of the acceleration.
It's important to note that the emission of electromagnetic waves by an accelerating electron is a fundamental principle in classical electrodynamics. However, at very high energies and velocities, quantum mechanical effects become significant, and a more detailed description of electron acceleration and radiation requires quantum electrodynamics (QED).