Ohm's Law relates current, voltage, and resistance; which formula is correct?

• A. I = V / R
• B. I = R / V
• C. I = V * R
• D. I = V - R

Answer: (A)

Current is the flow of electric charges, and Ohm’s Law shows how it depends on the driving force and the opposition to flow. The relationship is that the current through a conductor equals the voltage across it divided by the resistance: I = V / R. This means increasing voltage while leaving resistance the same pushes more current, while increasing resistance with the same voltage reduces current.

A quick check helps: with a 12-volt supply and a 6-ohm resistor, the current is 12/6 = 2 amperes. If the resistance rises to 12 ohms, the current drops to 1 ampere. The other forms don’t match this direct, inverse relationship or the proper units, so they don’t describe how current actually behaves.