Water Damage Restoration Technician (WRT) Certification Practice Test

Which surface temperature would result in the fastest rate of evaporation?

1. 10° below dew point

2. 20° above dew point

3. 30° above dew point

4. Equal to the dew point

The correct answer is: 30° above dew point

The fastest rate of evaporation occurs at a surface temperature that is significantly above the dew point. When the temperature is 30° above the dew point, the air has a greater capacity to hold moisture, reducing the relative humidity and allowing for more evaporation to occur. This is because the warmer the air, the more energy it possesses, which accelerates the process of converting liquid water into vapor. As temperature increases beyond the dew point, the excess thermal energy not only increases the kinetic energy of water molecules but also decreases the likelihood of condensation. In contrast, temperatures below the dew point would lead to condensation rather than evaporation, and temperatures equal to the dew point would create a saturated environment where evaporation slows significantly. Thus, maintaining a substantial temperature difference above the dew point contributes to a rapid transition from liquid to vapor, enhancing the evaporation process.