What is the current (Amps) of a circuit with a 9V battery and a 18Ω lamp?

A standard 9V battery has about 400-600 mAh capacity. In the most basic terms, these batteries can supply about 500 milliamps for one hour before being "dead". With electricity, we measure the amount of charge flowing through the circuit over a period of time. Current is measured in Amperes (usually just referred to as "Amps"). An ampere is defined as 6.241*10^18 electrons (1 Coulomb) per second passing through a point in a circuit. In a series circuit, amperage, or amplitude, of the current remains constant and can be calculated using Ohm's law V = I/R while the voltage drops across each resistor that can be summed up to get the total resistance.

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