HELP IN PHYSICS!

[Mahnoorfatima]

oK : SO THESE ARE SOME CONCEPTS THAT I DONT GET :
1. WHAT IS THE EFFECT OF HUMIDITY ON EVAPORATION
2. EFFECT OF PRESSURE ON EVAPORATION?

 

[Zuhsid]

oK : SO THESE ARE SOME CONCEPTS THAT I DONT GET :
1. WHAT IS THE EFFECT OF HUMIDITY ON EVAPORATION
2. EFFECT OF PRESSURE ON EVAPORATION?

Humidity: The basic concept is that when ever movement of particles is considered, a concentration gradient always has an affect. The higher the concentration the gradient, the higher the rate of movement. So if there is already water/liquid in the air(humidity), there will be a lower concentration gradient(than in dry air)...... so the rate of evaporation will be lower!!!

Pressure: Pressure is basically a force, a force that something(in this case air) exerts on the other things, so the larger the atmospheric pressure, the larger the force it exerts on the surface of the water/liquid, so in order to evaporate, the liquid first has to overcome the atmospheric pressure than have more force to get free(as the pressure is holding the water molecules down)..... Hence larger pressure=lower rate of evaporation!!! (As if the atmospheric pressure is low, the liquid will need less force to be set free, its force is the kinetic energy it gets from heat!!!)