Firefighter 1C Wildland Practice Exam

Relative humidity is the ratio of the amount of water vapor present in the air compared to:

1. the amount of water that it would make if it came out of the vapor state.

2. the maximum amount the air can hold at a given temperature.

3. the amount that would totally exclude the oxygen in that volume of air.

4. the amount of oxygen in the same volume of air at that particular time.

The correct answer is: the maximum amount the air can hold at a given temperature.

Relative humidity is defined as the ratio of the current amount of water vapor in the air to the maximum amount of water vapor that the air can hold at a specific temperature. This concept is crucial in understanding weather patterns, moisture content, and overall atmospheric conditions. When air temperature increases, its capacity to hold water vapor also increases; thus, relative humidity varies with temperature. If air is fully saturated with moisture, relative humidity reaches 100%, indicating that it cannot hold any more water vapor without condensation occurring. Therefore, the correct answer accurately reflects this fundamental relationship: relative humidity reflects how much moisture is present compared to the total moisture capacity of the air at that temperature. The other options do not accurately represent the standard definition of relative humidity, focusing instead on aspects that do not pertain to moisture saturation in the air.