posted by Josh .
Does atomic excitation occur in solids as well as in gases? Yes or No and Why?
Physics Help -
Atomic excitation occurs in solids, liquids, and gases. Because atoms in a solid are close packed, radiation from them (and liquids) is smeared into a broad distribution to produce a continuous spectrum, whereas radiation from widely-spaced atoms in a gas is in separate bunches that produce discrete “lines” when diffracted by a grating.