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تسجيل

The Unit of Resistance

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-354

2025-12-28

647

The ohm is defined as the resistance of a column of mercury the mass of which is 14.4521 g. and which has a uniform cross section, and a length of 106.3 ± cm. at 0° C. This is practically a column 106.3 cm. long and 1 sq. mm. in cross section. Ten feet of No. 30 copper wire has a resistance of 1.033 ohms. A megohm is a million ohms. A microohm is one millionth of an ohm.