Final answer:
The dry bulb temperature at the exit of an air washer with continuous water recirculation cannot be precisely calculated without specific inlet temperatures or other relevant data. The reduction in wet bulb depression to 25% at the exit suggests that the air has become more humidified than at the inlet.
Step-by-step explanation:
When air is humidified in an air washer operating with continuous water recirculation, several temperature readings are relevant. One such temperature is the dry bulb temperature, which is the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. Another important temperature is the wet bulb temperature, which is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only. The difference between the dry and wet bulb temperatures is known as the wet bulb depression.
The question specifies that the wet bulb depression at the exit is 25% of that at the inlet. Without the specific inlet temperatures or additional details, direct calculation of the dry bulb temperature at the exit is not possible. However, the understanding is that the decrease in the wet bulb depression indicates that the air has become more humid after passing through the air washer, as the temperature of the air approaches the wet bulb temperature.