1 For severe stains, add 1-2 cups vinegar to the wash cycle as well. 2  To remove a rust stain from your cotton work clothes, moisten the spot with some full-strength vinegar and then rub in a bit of salt. 3  If itâs warm outdoors, let it dry in the sunlight (otherwise a sunny window will do), then toss it in the wash.
absorption spectrum - the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths. spectrum - an ordered array of the components of an emission or wave.
A star is a hot dense ball of gas so we should expect it have a continuous spectrum. But stars also have thin, transparent outer layers that light has to pass through. These layers produce absorption lines. Thus the light from the sun and stars are examples of absorption spectra.The stars' spectra differ from each other depending on temperature and composition. When astronomers first observed these differences in the 19 th century they devised a classification system that assigned letters to various spectral types.he lines occur where atoms of the gas have absorbed specific wavelengths of light. Hence we call this type of spectrum an absorption spectrum. If we view this transparent gas against a black background we would see that it also emits light (if it has an enough energy), giving an emission spectrum.