Ans. The volt-coulomb.
A volt-coulomb of work is performed when one ampere of current flows for one second in a circuit whose resistance is one ohm, when the pressure is one volt.
The Ampere-Hour.—A gallon of water may be drawn from a hydrant in a minute, or in an hour; it is still one gallon. So in electricity, a given amount of the current, say one coulomb, may be obtained in a second or in an hour.
The ampere is the unit rate of flow.
What is called the electric current is simply the relation of any quantity of electricity passed to the time it is passing; that is
quantity in coulombs = current in amperes × time in seconds, or simply
coulomb = ampere × second.
Again:
10 coulombs = 2 amperes × 5 seconds = 10 amperes × 1 second = 1 ampere × 10 seconds, etc.
One ampere-hour is simply another way of saying 3,600 coulombs. Of course 3,600 coulombs of electricity may be obtained in any desired time. It all depends on the rate of flow or the current strength in amperes.