What form of energy emission accompanies the return of excited electrons to the ground state?

Electromagnetic radiation

Explanation:

When an excited electron returns to the ground state, it releases the excess energy as a quantum of electromagnetic radiation.

The wavelength of the radiation can vary from about 100 nm (the ultraviolet region) to about 10 000 nm (the infrared region).

A small slice of this range (about 400 nm to 800 nm) is the visible region, where our eyes can detect the radiation as different colours of light.

When these electrons return to their ground state, several distinct energy emissions occur. Electrons may become excited when a sample of matter is heated or subjected to an electrical current. The energy electrons emit when returning to the ground state is electromagnetic radiation, or EMR.