Fraunhofer Lines

In physics and optics, the Fraunhofer lines are a set of spectral lines named for the German physicist Joseph von Fraunhofer (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectrum of the Sun.The English chemist William Hyde Wollaston was in 1802 the first person to note the appearance of a number of dark features in the solar spectrum. In 1814, Fraunhofer independently rediscovered the lines and began a systematic study and careful measurement of the wavelength of these features. In all, he mapped over 570 lines, and designated the principal features with the letters A through K, and weaker lines with other letters.
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The lines of the spectrun; especially and properly, the dark lines of the solar spectrum, so called because first accurately observed and interpreted by Fraunhofer, a German physicist.
  

Eng: fraunhofer lines
Urdu: سُورج کے طیف میں پیدا ہونے والے سیّاہ خطُوط جو بہت گرم مرکز کے گِرد نِسبتاً ٹھنڈے شیشے میں روشنی جذب ہونے کے باعِث پیدا ہوتے ہیں ۔ خَطُوطِ فَران ہوفَر ۔ طیفِ شَمسی کی سَیاہ لکِیریں ۔