Which of the following expresses Ohm's law?

Ohm's law is a fundamental principle in electrical engineering that establishes a relationship between voltage, current, and resistance in an electrical circuit. The law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, provided the temperature remains constant.

The expression V = IR captures this relationship perfectly. Here, V represents the voltage (in volts), I represents the current (in amperes), and R represents the resistance (in ohms). This formula indicates that for a given resistance, if the voltage increases, the current will also increase linearly, which is a key concept for understanding how electrical circuits behave.

The other expressions provided relate to electrical concepts but do not directly represent Ohm's law. For instance, P = VI pertains to power calculations where P is power (in watts), V is voltage, and I is current. Understanding the specific context in which these formulas are applied is crucial when studying electricity and circuits.