Figure 5-17: Kirchhoff’s Laws for Continuous, Absorption Line, and Emission Line Spectra Law 1: A hot, opaque body emits a continuous spectrum of light. Law 3: If this light is passed through a cloud of a cooler gas, the cloud absorbs light of certain specific wavelengths, leaving the light that passes directly through the cloud with an absorption line spectrum. Law 2: Atoms in a hot gas cloud collide energetically and emit light, creating an emission line spectrum that is unique to each type of atom. In each case the spectra is shown, as it would appear with a prism, and just below it, by a graph of intensity versus wavelength.