Which equation represents the relationship between pressure and volume at constant temperature?

The equation that represents the relationship between pressure and volume at constant temperature is expressed through Boyle's Law, which is accurately captured by the equation P1V1 = P2V2. Boyle's Law states that for a given mass of gas at constant temperature, the product of its pressure and volume remains constant. This means that if the volume increases, the pressure decreases and vice versa, as long as the temperature does not change.

In the context of the given equation, P1 and V1 represent the initial pressure and volume of the gas, while P2 and V2 represent the final pressure and volume after a change has occurred. This direct relationship shows that, upon rearranging or manipulating the equation, one can calculate the new pressure or volume if one of the conditions changes, provided the temperature remains constant throughout the process.

The other options relate to different gas laws or principles but do not specifically represent the relationship between pressure and volume under constant temperature conditions as effectively as the equation derived from Boyle's Law does.