The dew point of moist air becomes __________ with decrease in its relative humidity.

ANS:A - less than the wet bulb temperature

The correct explanation is as follows: When the relative humidity decreases, the air becomes drier. As the air becomes drier, its ability to hold moisture decreases. Therefore, the temperature at which the air becomes saturated with moisture, known as the dew point, decreases. Since the wet bulb temperature is the temperature indicated by a thermometer bulb covered with a wet cloth exposed to moving air, it remains relatively constant unless there is a change in humidity or other conditions. Therefore, when the relative humidity decreases, the dew point becomes less than the wet bulb temperature.