I=E/R or V/R This formula indicates that the amount of current flowing in a circuit is equal to the quotient obtained when the voltage value is divided by the resistance value.
Thus, if there are 10 volts impressed across a 5 ohm resistor, the current flow through the resistor is 2 amps.

An unknown value of either voltage or resistance can also be found by rearrangement of the formula. Voltage, for example, can be obtained if the values of current and resistance are known.

Because power is related to Ohm's law, the amount of power used can be used in formulas for finding unknown values of current and voltage.
I = P/E
R = P/I squared
E = the square root of PxR
I = the square root of P/R (power divided by resistance)