Ohm's law states that, At constant temperature, in an electrical circuit, the current passing through a conductor, from one terminal point on the conductor to another terminal point on the conductor, is directly proportional to the potetial difference (i.e. voltage drop or vltage) across the two terminal points and inversely proportional to the resistance of the conductor between the two terminal points.
In mathematical terms this is written as :
where I is the current, V is the potential difference, and R is a constant called the resistance. The potential difference is also known as the voltage drop, and is sometimes denoted by E or U instead of V.
For more information on this vsit the following sites :
http://www.csgnetwork.com/ohmslaw.html --- Ohm's law calculations