What happens when an electron drops from a higher energy level to a lower energy level

When an electron drops from a higher energy level to a lower energy level, the energy difference between the two levels is emitted as a photon of electromagnetic radiation. This is known as emission of light. The photon is released with a specific wavelength and frequency, which is directly related to the difference in energy between the two levels. This phenomenon is known as atomic emission spectrum and is frequently used to investigate the electronic structure of atoms and molecules.