Final answer:
Ampere-hours in a car battery correspond to the total charge that the battery can deliver over time, and the energy content of the battery is directly proportional to the ampere-hours when multiplied by the battery's voltage. Option b) Charge; directly proportional to energy content is the correct answer.
Step-by-step explanation:
Car batteries are rated in ampere-hours (Ah), which correlates to the total charge the battery can supply over time. Specifically, one ampere-hour represents the ability to supply a current of one ampere for an hour. Voltage, on the other hand, indicates the energy per unit charge and thus is distinct from ampere-hours.
Since charge capacity in batteries is characterized as Amp-hours, and because current multiplied by voltage equals power (watts), then ampere-hours multiplied by voltage gives us watt-hours. Watt-hours is a unit of energy, which indicates that the energy content of a battery is directly proportional to the ampere-hours rating. Therefore, knowing the voltage of the battery allows us to calculate the total energy content in the battery. The correct answer to the given options is: b) Charge; directly proportional to energy content.