Referring to the illustrated psychrometric chart, under what conditions are the dry- bulb, wet-bulb, and dew point temperatures for air all equal in value? GS-RA-22 Illustration GS-RA-22: the U.S. Coast Guard has not released this illustration.

Correct Answer: Option C — When the air is completed saturated with moisture and the relative humidity is 100%.

At 100% relative humidity, the air is fully saturated with water vapor. Under this condition, the air cannot hold any more moisture, meaning the dry-bulb, wet-bulb, and dew point temperatures are identical because evaporation cannot occur, and the air is already at its saturation temperature for the given pressure.