Final answer:
An absorption spectrum is observed when light passes through a gas and appears as black lines at certain wavelengths, representing the wavelengths of light that are absorbed by the gas. An emission spectrum is observed when light is emitted by a gas and appears as colorful lines on a dark background, representing the wavelengths of light that are emitted by the gas.
Step-by-step explanation:
Absorption and emission spectra are different for an element in gaseous form. An absorption spectrum is observed when light passes through a gas and appears as black lines at certain wavelengths. These black lines represent the wavelengths of light that are absorbed by the gas. On the other hand, an emission spectrum is observed when light is emitted by a gas and appears as colorful lines on a dark background. The positions of these emission lines represent the wavelengths of light that are emitted by the gas. Both the absorption and emission spectra provide valuable information about the composition and structure of the gas.