If light from a hot solid passes through a cooler gas, it produces a/an which spectrum?

If light from a hot solid passes through a cooler gas, it produces a/an which spectrum?

• A. Emission
• B. Absorption
• C. Scattering
• D. Continuous

Answer: (B)

When a hot solid emits, it produces a continuous spectrum. If that light then passes through a cooler gas, the atoms in the gas absorb photons at specific wavelengths that match their energy-level transitions. Those absorbed wavelengths are removed from the transmitted light, so the spectrum shows dark lines at particular colors against the bright continuum. This combination—the continuous background with dark absorption lines—is an absorption spectrum. If the gas were hotter than the source, you’d expect emission lines instead; if there were no absorption, you’d just have a continuous spectrum.

When a hot solid emits, it produces a continuous spectrum. If that light then passes through a cooler gas, the atoms in the gas absorb photons at specific wavelengths that match their energy-level transitions. Those absorbed wavelengths are removed from the transmitted light, so the spectrum shows dark lines at particular colors against the bright continuum. This combination—the continuous background with dark absorption lines—is an absorption spectrum. If the gas were hotter than the source, you’d expect emission lines instead; if there were no absorption, you’d just have a continuous spectrum.