The relative humidity of the air when the dry temperature is about 4 degrees and the dew point is about -4 degrees C is 56%. Hence option 4 is correct.
What is dewpoint?
The dew point is the temperature at which the air needs to be colled at a ta constant pressure in order to have an RH of 100%. The dew point is minus four degrees and the RH of the air is 4 degrees.
For the forces to initiate the air must get cooler and a constant addition of water pressure should be there. Thus substrating the temperature of the wet bulb, putting the thermometer on the dry bulb, and making use of the RH chart tells us that RH is 56%
Find out more information about the relative humidity.
brainly.com/question/5369085