Stuart:
Allow me to dredge up my 12th Grade Physics...
Keep in mind that the Law of Conservation of Energy applies here, too. Ohm's law doesn't get to have all of the fun.
Some Physics Guy:
The law states that the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system. In other words, energy can be converted from one form to another, but it cannot be created or destroyed.
You have x amount of energy going into the rheostat switch. You have y amount of energy coming out.
Because of the resistence in that rheostat, the value of y is always going to be less than that of x.
Since the law states both sides must be equal (energy cannot be created or destroyed, only modified), you then have z amount of energy tied up in heat production.
So, we have x (incoming energy) = y (outgoing energy) + z (heat producing energy).
The lower the value in y, the greater the value in z, so if you have your heater turned down to low, the switch will get VERY hot.
Hope that this made sense. They're remodeling the bathrooms on this floor and they're playing with torches and getting us all buzzed.
