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Grade 12 Science · Problem type
Matching a star’s lines to elements
Use this for “Which elements are in this star?” from its dark lines and lab spectra.
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The star’s light, spread into a rainbow, has dark lines where some wavelengths are missing.
Below it are the bright lines of hydrogen, helium and sodium measured in a lab.
Assumptions
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Each element absorbs and gives off light only at its own wavelengths: its lines are a fingerprint.
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Cooler gas in a star’s outer layers absorbs those wavelengths, leaving dark lines in its rainbow.
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An element is in the star only if every one of its lines appears there.
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Light, spectra, telescopes and distances to stars
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