What is the relative humidity on a $25.0^{\circ }\text{C}$ day when the air contains $18.0{\text{ g/m}}^3$ of water vapor?

Video Transcript

This is College Physics Answers with Shaun Dychko. Relative humidity is the vapor density divided by the saturation vapor density, so this is the maximum vapor density. And at 25 degrees Celsius we can see at Table 13.5 that the saturation vapor density is 23.0 grams per cubic meter. So, the relative humidity then is going to be this 18 grams per cubic meter divided by the maximum times 100 percent giving us 78.3 percent relative humidity.