All spontaneous processes release free energy
It is called surface tension it is the elastic personality of some liquids as they pull together to take up as little surface area as possible. the water molecules would rather stay together than be pulled apart<span />
To solve this problem we will apply the concepts related to electric potential and electric potential energy. By definition we know that the electric potential is determined under the function:

= Coulomb's constant
q = Charge
r = Radius
At the same time

The values of variables are the same, then if we replace in a single equation we have this expression,

If we replace the values, we have finally that the charge is,




Therefore the potential energy of the system is 
P=IV, where P is power, I is resistance, and V is voltage. Plug in and solve:
P=400(20)
P=8000W
Hope this helps!!
Some are fuel,chemicals,plastics,asphalt,and road oil.