Final answer:
The rate of evaporation (J) increases with an increase in the proportionality factor (K) within the formula J=K [(WVPs-WVPa)/ X], with additional considerations for temperature and humidity's impact on water vapor pressures.
Step-by-step explanation:
Referring to the formula J=K [(WVPs-WVPa)/ X], it suggests that the rate of evaporation, J, will increase with an increase in the proportionality factor K. By understanding the relationship between evaporation and environmental factors, we can deduce that the rate of evaporation is influenced by the difference in water vapor pressure (WVP) between the surface (WVPs) and the air (WVPa), as well as the distance X. Other factors such as temperature, humidity, and the characteristics of the evaporating surface also play significant roles.
For instance, humidity affects the WVPa, with higher humidity leading to a reduced evaporation rate because the difference in water vapor pressure between the surface and the air decreases (c. Increasing humidity leads to reduced evaporation rates due to decreased difference in water vapor pressure between leaf and atmosphere). On the other hand, an increase in temperature tends to increase the evaporation rate by increasing the water vapor pressure of the surface, up to the saturation point. After this point, the rate will plateau as equilibrium is reached between evaporation and condensation rates.