Ohm's law comes from dividing voltage by current. What do we get when we multiply voltage by current?
This is the same quantity we saw when
mechanical work was done per unit time. Go
to mechanical power. Thus by knowing the voltage across a
resistor and the current passing through a resistor, we can determine
the rate at which energy is consumed by the resistor. P = V x
I. When V is measured in volts and I in amperes, P is measured
in watts.
Central Maine Power Company
Central Maine Power Company sells a commodity in units of kwh. A 100 W energized for 10 hours will cause the owner to be billed for 1000 W-hrs = 1 kW-hr. What kind of unit is a kwh? Strangely enough, it is not a unit of power.
It may also prove useful to examine your family's monthly power bill.
Like to do an electrical energy inventory
for your home? Try
http://zebu.uoregon.edu/nsf/circuit.html#Ohm
Last edited 12/24/05