Final answer:
Ohm's law describes the direct proportionality between current and voltage and the inverse proportionality between current and resistance in a DC circuit, typically represented as V = IR.
Step-by-step explanation:
The relationship between current, voltage, and resistance in a DC circuit is described by Ohm's law. This fundamental relationship can be expressed using the formula V = IR, where V represents voltage, I stands for current, and R symbolizes resistance. The law shows that the current (I) in a circuit is directly proportional to the voltage (V) and inversely proportional to the resistance (R). An ohmmeter is a tool that applies a voltage to measure resistance by first measuring current and then using Ohm's law to calculate the resistance.
Ohm's law is considered an empirical law, similar to the law for friction, which has been determined through experimentation. The law illustrates a cause-and-effect relationship, with the voltage as the cause that drives the flow of current through the circuit and the resistance being the factor that impedes it. It's important to note that this linear relationship does not always occur, as it is valid only under certain conditions and for particular types of materials.