Question

If the relative humidity is 90.0% on a muggy summer morning when the temperature is [Math Processing Error], what will it be later in the day when the temperature is [Math Processing Error], assuming the water vapor density remains constant?

a. 90.0%
b. Greater than 90.0%
c. Less than 90.0%
d. None

Answer 1

If the temperature rises from 20.0°C to 30.0°C and the water vapor density remains constant, the relative humidity will be less than 90.0% because the increased temperature allows air to hold more water vapor.

Step-by-step explanation:

Relative humidity is the ratio of the current amount of water vapor in the air to the maximum amount of water vapor the air can hold at that temperature, expressed as a percentage. When the temperature rises, the air can hold more moisture. Assuming the water vapor density remains constant, if the temperature increases from 20.0°C to 30.0°C, the amount of water vapor the air can hold also increases. Therefore, relative humidity decreases because the same amount of water vapor represents a smaller percentage of the new, higher capacity for water vapor at 30.0°C.

The answer to the question, therefore, is (c) less than 90.0%.