Final answer:
A battery's capacity is measured by the product of current supplied and the length of time it is supplied (Amp-hours or mAh). This calculation reflects the total charge a battery can hold, when considering its voltage and charge capacity.
Step-by-step explanation:
The capacity of a battery is measured by the product of the current supplied and the length of time it can be supplied, which is answer choice a. Current supplied * length of time supplied. This measurement is typically expressed in Amp-hours (Ah) or milliamp-hours (mAh). As current is defined as charge per unit time, multiplying the current by the time gives us the total charge, which is the charge capacity of the battery. In practice, this means that a battery's ability to hold energy is characterized by its voltage and charge capacity.
To determine the internal resistance of a battery, one could use an assortment of resistors and voltage and current measuring devices. By measuring the voltage and current in a circuit with known resistances, it's possible to calculate the internal resistance of the battery.
Regarding power and energy delivered by a battery, knowing the voltage (V) and current (A) also allows the calculation of power in watts (W), since power (P) is the product of voltage and current (P = V * A). The energy delivered can be calculated by multiplying the power by the time for which it is delivered.