A Level Physics Practice Exam

Power is measured in Watts, which is defined as the rate at which energy is transferred or converted. Specifically, one Watt is equivalent to one Joule per second. This means that if a device uses one Joule of energy in one second, it has a power output of one Watt. Understanding this relationship highlights that power is fundamentally linked to both energy and time. Joules are a unit of energy, and while they are related to power, they do not measure the rate of energy transfer. Volts measure electric potential difference, which is different from power, and Amperes measure electric current, indicating the flow of electric charge. Therefore, the only appropriate unit for measuring power among the options provided is Watts.