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Second Law of the Spectrum

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-482

2025-12-21

380

Second Law of the Spectrum-Demonstration.-Dip a platinum wire in a solution of salt and hold it in a nonluminous Bunsen flame; or soak a strip of cloth or asbestos in salt water and wind it around the top of a Bunsen burner. Examine the flame with the spectroscope, and instead of a continuous spectrum, a bright yellow band will be seen in the middle of the place occupied by the yellow of the continuous spectrum.This yellow band is called the sodium line, or D line, and on being closely studied is seen to be made up of two narrow bright lines with a dark band between them.

LAW II. Incandescent gases, not under great pressure, give a spectrum made up of bright colored lines on a dark background.

Each line has a definite position in the spectrum, and is characteristic of the substance which produces it.