### Theory:

Georg Simon Ohm, a German physicist, conducted various experiments and formulated Ohm's law. The law describes the relationship between potential difference and current.

Ohm's law states that,
At a constant temperature, the steady current '$$I$$' flowing through a conductor is directly proportional to the potential difference '$$V$$' between the two ends of the conductor.
Mathematically, it is written as

$I\phantom{\rule{0.147em}{0ex}}\mathrm{\alpha }\phantom{\rule{0.147em}{0ex}}V$

Hence,

$\frac{I}{V}=\mathit{constant}$

(or)

$I=\left(\mathit{constant}\right)\phantom{\rule{0.147em}{0ex}}V$
The value of the proportionality constant found in the above equation is $\frac{1}{R}$.

Therefore,

$\begin{array}{l}I=\frac{1}{R} V\\ \\ V=\mathit{IR}\end{array}$

Where $$V$$ is the potential difference, $$I$$ is the current flowing through a conductor, and $$R$$ is the resistance of a material. The resistance is constant for a material (e.g., copper) at a given temperature.

The above equation can also be written as,

$R=\frac{V}{I}$

In terms of units, the resistance $$R$$ of a conductor is said to be $$1\ ohm$$ with a potential difference of $$1\ volt$$, causing the current of $$1\ ampere$$ to flow through the conductor. Then,

$\mathit{Ohm}=\phantom{\rule{0.147em}{0ex}}\frac{\mathit{Volt}}{\mathit{Ampere}}$

Graphical representation:
The graph between the potential difference ($$V$$) and the current ($$I$$) is a straight line for a conductor since $$V$$ is proportional to $$I$$.

The relation between potential difference and current