Which type of spectrum does not consist of continuous wavelengths but consists of distinct lines?

The correct choice is the line spectrum, which is characterized by distinct lines that represent specific wavelengths of light emitted or absorbed by a substance. This type of spectrum arises from the transitions of electrons between energy levels in atoms. When an electron absorbs energy, it moves to a higher energy level; conversely, when it returns to a lower energy level, it releases energy in the form of light at specific wavelengths. The result is a spectrum with sharp lines corresponding to these transitions, rather than a continuous range of wavelengths.

In contrast, a continuous spectrum features a seamless blend of colors, covering a wide range of wavelengths without any gaps. Emission spectra can consist of line spectra when viewed under specific contexts, as they show the wavelengths emitted by electrons transitioning down to lower energy levels. Absorption spectra involve the absorption of specific wavelengths of light by atoms or molecules, leading to dark lines against a continuous spectrum usually produced by a hot source. Each of these types of spectra provides valuable information correlating to atomic and molecular structures, but only the line spectrum distinctly exhibits separate lines indicating particular wavelengths.