Which formula relates current, resistance, and voltage in a simple resistor circuit?

• A. V = I × R
• B. V = I / R
• C. V = R × I^2
• D. V = I + R

Answer: (A)

This question centers on Ohm's Law, which describes how voltage, current, and resistance relate in a resistor. The law states that the voltage across a resistor equals the current through it times its resistance: V = I × R. This makes intuitive sense: the voltage provides the push that drives current, and for a fixed resistance, increasing the voltage increases the current proportionally.

The units also line up neatly: volts equal amperes times ohms, so V = IR is dimensionally correct. The other forms don’t fit the relationship: V = I / R would mix units incorrectly and isn’t how voltage relates to current and resistance; V = R × I^2 corresponds to the power relationship P = I^2R (not voltage itself); and V = I + R adds unlike quantities (current and resistance) and doesn’t produce volts.