The difference in the readings on the dry and wet bulb thermometers is used to determine?

The difference in the readings on the dry and wet bulb thermometers is used to determine the relative humidity of the air. The dry bulb thermometer measures the ambient temperature of the air, while the wet bulb thermometer measures the temperature with the effect of evaporative cooling. The difference between the two temperatures, known as the "wet bulb depression," is a function of the humidity in the air. By comparing the wet bulb depression to a chart or calculator, you can determine the relative humidity of the air. Relative humidity is the amount of moisture in the air compared to the maximum amount the air can hold at a given temperature. So, the difference in readings on the dry and wet bulb thermometers can tell you how much moisture is in the air, which allows you to calculate the relative humidity.