Final answer:
The unit of power to measure electricity is D. Watt, which is the rate of energy use measured in joules per second. Kilowatt-hours represent the total energy consumption over time, equivalent to 3.6×10^6 joules.
Step-by-step explanation:
The unit of power used to measure electricity is D. Watt. A watt (W) is a unit of power, which represents the rate at which energy is used or given off per unit time, and is measured in joules per second (J/s). For example, a 100-watt light bulb uses 100 joules of energy every second. The kilowatt (kW), which is equal to one thousand watts, is commonly used for larger energy consumers like engines or heaters. Moreover, energy consumption is often measured in kilowatt-hours (kWh), which reflects the energy used by a device using power P for a time interval t. This is because 1 kWh is equivalent to 3.6×106 joules, and it relates directly to the cost of electricity in terms of power consumption over time, which is practical information for consumers.
When discussing power and energy, it is important not to confuse terms such as "kilowatts per hour," which is incorrect, with "kilowatts" as a rate of energy use, measured in joules per second. Instead, kilowatt-hours is a cumulative measure of energy used over time.