How much heat is required to raise the temperature of 1 pound of water by 1 degree Fahrenheit?

The correct answer is based on the definition of a British thermal unit (Btu). A Btu is specifically defined as the amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit. This foundational unit of measurement in thermodynamics applies to various heating and cooling processes and is crucial for understanding energy transfer.

When you consider the other options, they suggest different quantities of energy required. However, since the definition of a Btu is established to be exactly the amount necessary to raise the temperature of 1 pound of water by 1 degree Fahrenheit, any value outside of 1 Btu is incorrect in this context. This clear definition supports the understanding of energy consumption in heating applications and establishes a reference point for heating calculations in operating engineering.