What is Ohm's Law as given?

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

Answer: (A)

Ohm’s Law shows how voltage, current, and resistance relate to each other. The basic idea is that the voltage across a conductor equals the current through it times its resistance: V = I × R. From that, you can rearrange to solve for any one quantity in terms of the other two. The form R = V / I is just solving V = IR for the resistance. It says: the resistance is the ratio of voltage to current. For example, if you have 6 volts and a current of 2 amperes, the resistance is 6 / 2 = 3 ohms, and then V = I × R checks out (2 × 3 = 6). So this form is equally valid and often convenient when you know voltage and current and want the resistance. The other standard forms, V = IR and I = V / R, are just the same relationship written for different unknowns.