Which formula can you use to solve for voltage?

Which formula can you use to solve for voltage?

• A. V = P * I
• B. V = I / P
• C. V = P / I
• D. V = R * I

Answer: (C)

Power in a circuit is the product of voltage and current (P = V × I). To solve for voltage when you know power and current, rearrange this equation to V = P / I. This directly follows from the definition and gives the correct units: watts divided by amperes leaves volts. For example, if a device uses 60 watts and draws 2 amperes, the voltage is 60 ÷ 2 = 30 volts. Note that V = I × R would give voltage when you know resistance, but that’s a different relationship. The other options would not yield volts in this scenario: multiplying power by current isn’t the correct rearrangement, and current divided by power has the wrong units.

Power in a circuit is the product of voltage and current (P = V × I). To solve for voltage when you know power and current, rearrange this equation to V = P / I. This directly follows from the definition and gives the correct units: watts divided by amperes leaves volts. For example, if a device uses 60 watts and draws 2 amperes, the voltage is 60 ÷ 2 = 30 volts.

Note that V = I × R would give voltage when you know resistance, but that’s a different relationship. The other options would not yield volts in this scenario: multiplying power by current isn’t the correct rearrangement, and current divided by power has the wrong units.