Answer:
emission line or absorption line
Explanation:
A spectral line is uniform bands of bright and dark fringes. visible spectrum are just due to string spectral line which is unique for a different element.
when there is the transmission of an electron from one energy to another ( higher to lower energy level), there is the emission of photons that lead to emission-line on the spectrum while on the other side, the absorption line is formed when electron moves to the next level by absorbing electron.
