Q1: The wet bulb temperature is lower in dry air than in wet air at the same temperature. A dry bulb thermometer registers a higher temperature than a wet bulb thermometer except at __________ percent relative humidity.

ANS:B - 100

A dry bulb thermometer registers a higher temperature than a wet bulb thermometer except at 100 percent relative humidity. Explanation:

• The dry bulb thermometer measures the ambient air temperature, regardless of moisture content.
• The wet bulb thermometer measures the temperature of air when water evaporates from a wet surface, which cools the thermometer due to evaporative cooling.
• When the air is dry (low humidity), water evaporates more readily from the wet bulb, causing greater evaporative cooling and thus a lower wet bulb temperature compared to the dry bulb temperature.
• At 100 percent relative humidity, the air is saturated with water vapor, and evaporation ceases. Therefore, the wet bulb thermometer will show the same temperature as the dry bulb thermometer because there is no evaporative cooling effect.