Relating the concepts of
Electrical Power
And
Ohm's Law

Objectives- students will learn the relations between ohm's law and the concept of electrical power

        Ohm's law states that eletrical resistance is the ratio between the voltage and current of the currict.  The concept of electrical power states that power is the product of current and voltage.  So using these two concepts you can combine the two equaltions to simplify your work.

Equations

Ohm's law
V = W x A

Electrical power
W = V x A

So can create two new equaltions from these two.

if you know power and volts you can find restitance
W = V²/ w
 

If you know power and restitance you can find current
A² = W/W
 

Sample Equations

1. A currcuit uses a voltage of 12 volts and produces 3 watts of power.  Solve for the resistance.
W = V²/W
W = (12)²/(3)
Resistance =48 W

2. A current has a resistance of 60W and a power of 15 watts slove for the current

A² = W/W
A² = (15)/(60)
current = .5 amps