How many kilojoules are equivalent to one watt-hour?

To understand why 3.6 kJ is the correct answer for how many kilojoules are equivalent to one watt-hour, it's important to recognize the relationship between watts, joules, and kilojoules.

A watt is defined as one joule per second. Therefore, when we say one watt-hour, we are discussing the energy consumed or produced when one watt of power is used for one hour.

To convert watt-hours to joules, the calculation is as follows:

1 watt-hour = 1 watt × 1 hour = 1 joule/second × 3600 seconds = 3600 joules.

Now, since 1 kilojoule (kJ) is equal to 1000 joules, we convert joules to kilojoules:

3600 joules ÷ 1000 = 3.6 kJ.

This shows that one watt-hour indeed equals 3.6 kilojoules, confirming that the correct choice is 3.6 kJ. Understanding these units of energy and their conversions is crucial in power engineering, as it aids in the calculation and assessment of electrical consumption and production.