What is the name of the law that describes the relationship in an electrical circuit of voltage, current, and resistance?

• A. Kirchhoff's Law
• B. Ohm's Law
• C. Joule's Law
• D. Faraday's Law

Answer: (B)

Ohm’s Law describes how voltage, current, and resistance relate in an electrical circuit. It states that voltage equals current times resistance (V = I × R), so you can rearrange to find any one quantity if you know the other two (I = V / R, R = V / I). In practice, this means doubling the voltage while keeping resistance fixed doubles the current, and increasing resistance with the same voltage reduces the current.

This is especially useful in aviation maintenance when you’re diagnosing circuits or predicting how a component will draw current from a power source. For example, in a 12-volt system with 4 ohms of resistance, the current would be 3 amperes (I = 12 V / 4 Ω). Other listed laws relate to different phenomena: Kirchhoff’s Law deals with current and voltage sums in circuits, Faraday’s Law concerns induced voltage from changing magnetic fields, and Joule’s Law describes heat produced by current.