Question

the ____ of energy from matter occurs when its electrons are excited and move to a higher energy level and then return to a lower energy level. emission frequency wavelength diffraction

Explanation:

When electrons are excited and then return to a lower energy level, energy is released. This process is called emission. Frequency refers to the number of wave cycles per unit time. Wavelength is the distance between successive crests of a wave. Diffraction is the bending of waves around obstacles.

Answer:

emission