Answer:
It is called a line spectrum.
Explanation:
When an atom jumps from one energy level to a higher one, it is said that it is in an excited state.
As the normal behavior is to be at a ground energy level (unexcited state), the atom tries to return to this state as soon as possible.
When doing this, it emits a photon of a distinct wavelength, which depends on the transition type.
As there are only some allowed transitions possible, the possible wavelengths are a discrete set too.
So, when projected on a photosensitive screen, the different colors form a set of discrete lines, so this specific pattern of colors is called a line spectrum.
