Which of the following is not equivalent to a unit of thermal energy?

A watt is a unit of power, not a direct measurement of thermal energy like the other options. Thermal energy measures the total kinetic energy of the particles in a substance, and it can be quantified in terms of BTUs (British Thermal Units), kilowatt-hours (kWh), and therms.

A BTU represents the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. A therm is a larger unit of heat energy often used to measure the energy content of natural gas, equivalent to 100,000 BTUs, making it clear that both BTU and therm are specific measures of thermal energy.

Similarly, a kilowatt-hour measures electrical energy over time and can also be converted to thermal energy, translating into a specific amount of heat generated. In contrast, a watt measures the rate of energy transfer, indicating how much energy is being used or produced per second, and does not quantify thermal energy directly. Thus, it is not equivalent to a unit of thermal energy.