Spectroscopy shows what elements are present in the star, it's chemical composition. The different elements give off different energy signatures through radiation, which relate to the wavelength and...
A star's spectrum can tell you what elements the star is made out of, the temperature of the star, how/if a star is moving, the density of the star and much, much more. The color of stars are...
The information that could be obtained from observing a star's spectrum would be where it possibly could be on the Hertzsprung-Russell Diagram, its luminosity (brightness), its color, the type of...