We know that condensed matter (solids and liquids) and dense gases at
all temperatures emit electromagnetic radiation in which a continuous
distribution of several wavelengths is present, though with different
intensities This radiation is considered to be due to oscillations of atoms
Chapter Twelve
ATOMS
Rationalised 2023-24
291
Atoms
and molecules, governed by the interaction of each atom or
molecule with its neighbours In contrast, light emitted from
rarefied gases heated in a flame, or excited electrically in a
glow tube such as the familiar neon sign or mercury vapour
light has only certain discrete wavelengths The spectrum
appears as a series of bright lines