Many persons who have devoted no time to the study of physics wonder what the force is that drives the street-car along—turning its wheels, while at the same time furnishing incandescent lamps (light) for the passengers. They have been told, of course, that the “power” used is “electricity”, generated by dynamos “at the power-house”, and conveyed to the rapidly moving car by the overhead wire. “Electricity: yes, but what is electricity?” This is a natural and perfectly legitimate question for a layman to ask.…
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