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Friction Develops Both Kinds of Electricity

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-323

2025-11-27

521

Demonstration. - Rub a glass rod and an ebonite rod together, much as a mower whets his scythe. Test each by bringing it near the knob of an electroscope. The glass will be found to be charged positively and the ebonite will show an equal negative charge.

 Tests carefully made by rubbing various substances together show not only that both kinds of electricity are produced, but also that the opposite charges generated are equal in amount. For instance, the + charge generated upon a glass rod is the same in quantity as the - charge generated upon the silk by which it is rubbed.