Which equation represents Ohm's Law in a resistive circuit?

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

Answer: (B)

In a resistor, voltage, current, and resistance relate linearly: the voltage across the component equals the current through it times its resistance. This simple relationship is Ohm’s Law.

The direct form is the equation V equals I times R. It shows exactly how voltage depends on current for a given resistance, and you can rearrange it to find the other two quantities: I = V / R or R = V / I.

Why the other forms don’t fit here: I = V × R would not have the correct units to describe current, since volts times ohms doesn’t yield amperes. The equation P = VI describes electrical power, not the basic voltage-current-resistance relationship. R = V ÷ I is a valid rearrangement, but the most straightforward representation of Ohm’s Law in a resistive circuit is V = IR.