What is the capacity of a battery measured in?

The capacity of a battery is measured in amp-hours (Ah), which indicates how much current (in amperes) the battery can supply over a certain period of time, usually one hour. This measurement is essential for determining the battery's ability to maintain a load before it needs recharging. For example, a battery rated at 10 amp-hours can deliver 10 amps of current for one hour, or two amps for five hours, emphasizing its ability to provide a specific amount of energy over time.

While voltage represents the electric potential provided by the battery and watt-hours measure the total energy capacity (voltage multiplied by the amp-hour rating), they do not specifically reflect the battery's capacity in terms of duration of current supply. Ohm is a unit of resistance and does not pertain to battery capacity directly. Understanding the amp-hour measurement is crucial for assessing how long a battery can power a device before requiring a recharge, making it the correct answer to the question about battery capacity.