Ohm is the standard unit of electrical resistance named after Georg Simon Ohm, who introduced Ohm's law that first appeared in the book Die galvanische Kette, mathematisch bearbeitet in 1827, and explains his complete theory of electricity.
"The current in an electrical circuit is directly proportional to the voltage and inversely proportional to the resistance."
Below is the formula to calculate the various values used in Ohm's Law.
V=Voltage I=Current R=Resistance
V=I*R I=V/R R=V/I