Question

How does evaporation increase with the decrease of humidity

Answer 1

Humidity is inversely proportional to the rate of evaporation. So the rate of evaporation at a given place is always dependent on the humidity of that place. If the air is already filled with water vapor, it will not have any place to hold excess vapor and therefore, evaporation will occur at an extremely slow rate. Hence the more is the humidity in the sorroundings, lower will be the rate of evaporation and lower is the humidity, the more will be the evaporation.