What is Ohm's law and calculation

Ohm's law and calculation for a guide to technicians

Ohm's law 
        Ohm's law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points.

Example: If  - V = 230, R = 10 Ohms I = ?

                      I = V / R
                      I =  230 /10
The answer is = 23 Amps in DC volt