Ohm's Law formula is V = IR. Which of the following expresses Ohm's Law in a way that is clearly incorrect?

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

Answer: (D)

Understanding Ohm's Law means recognizing how voltage, current, and resistance relate through V = IR. If you try to express current as I = V × R, you’re multiplying voltage by resistance, which doesn’t give current in the correct units or meaning. The correct rearrangements from Ohm’s Law are I = V / R and R = V / I, dividing by the other quantity, not multiplying. Expressing power as P = VI is a valid relationship, but it describes power, not the direct V–I–R link of Ohm’s Law. So the forms that multiply V with R (or with I) to equal another quantity are the clearly incorrect ones, while V = IR is the correct foundational expression.