What is Ohm's Law in its common form for calculating voltage?

• A. V = I × R
• B. I = V × R
• C. V = R ÷ I
• D. P = V × I

Answer: (A)

Voltage is the driving force that pushes current through a circuit, and Ohm's Law links voltage, current, and resistance. The common form for calculating voltage is V = I × R, which directly shows that voltage equals current times resistance. When you know the current flowing through a conductor and its resistance, multiply them to find the voltage across it. For example, 2 A through a 5 Ω resistor gives 10 V.

Other forms don’t calculate voltage in the same way: current is V ÷ R, not V × R; using V × R would mix units and isn’t a valid way to get current. The expression P = V × I gives power, not voltage. So the correct formula for voltage is V = I × R.