Ohm's law

Science

Definition

Ohm's law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance. It is the fundamental relationship used to analyze electrical circuits.

Examples

  • A 12V battery connected to a 4Ω resistor produces a current of 3A
  • Increasing the resistance in a circuit (like using a longer wire) decreases the current if voltage stays the same
  • Electricians use Ohm's law to determine the correct wire gauge needed for a given appliance
Key Fact

V = IR, where V is voltage (volts), I is current (amps), and R is resistance (ohms).

Related Terms

Circuits Series and parallel Electric charge Electromagnetic induction

Study This Concept

Practice Ohm's law with free review games in these units:

Physics Unit 8: Electricity