Lines present in atomic emission spectra are - Solution The emission lines are specific wavelengths where the atom or molecule has emitted photons. Since light is quantized, atoms and molecules can have energy levels that correspond to specific photon wavelengths. When a particle transitions from a higher energy to a lower energy a photon is emitted. These are the emission lines. These energy emmited from element are bright where electron emits some specific amount of energy when it moves from Upper energy level to low energy level. Nd the area where lights are absirbed seen as dark line in emmision spectra. . .