Ohm's law states that the electric current flowing through a conductor is directly proportional to the potential difference across its two ends, when other physical conditions like temperature etc., remain constant.i.e., or$V \propto I$$\frac{V}{I} = \text{ Constant } = R$$V = IR$orThus, the ratio $V : I$ is a constant. This constant is called the resistance (R) of the conductor. Circuit diagram for Ohm's law :If a graph is drawn between the potential difference (V) and current (I), the graph is found to be a straight line passing through the origin. This shows that the current is directly proportional to the potential difference. Thus, the ratio $\; \frac{V}{I}$ remains constant. This constant is called the resistance of the conductor. The gradient of the straight line graph is related to the resistance $(R)$ of the conductor.