Which equation correctly represents the voltage drop across a conductor with current I and resistance R?

Which equation correctly represents the voltage drop across a conductor with current I and resistance R?

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

Answer: (A)

Voltage drop across a conductor is dictated by Ohm's Law: V = I × R. This means the potential difference the current experiences as it flows through the conductor equals the current times the conductor’s resistance. The units align naturally: amperes times ohms give volts. For example, 2 A through 3 Ω yields a 6 V drop. The other expressions don’t describe a voltage drop: R ÷ I would have wrong units; I × V equals power in watts; and adding R and I mixes incompatible quantities. So the correct representation is V = I × R.

Voltage drop across a conductor is dictated by Ohm's Law: V = I × R. This means the potential difference the current experiences as it flows through the conductor equals the current times the conductor’s resistance. The units align naturally: amperes times ohms give volts. For example, 2 A through 3 Ω yields a 6 V drop. The other expressions don’t describe a voltage drop: R ÷ I would have wrong units; I × V equals power in watts; and adding R and I mixes incompatible quantities. So the correct representation is V = I × R.