Define electric current and state its $SI$ unit. With the help of $Ohm's$ law,explain the meaning of $1$ ohm resistance.

(N/A) Electric current is defined as the rate of flow of electric charge through a conductor.
The $SI$ unit of electric current is the ampere $(A)$.
According to $Ohm's$ law,$V = I \times R$,where $V$ is the potential difference,$I$ is the current,and $R$ is the resistance.
From this,$R = V / I$.
If the potential difference across a conductor is $1$ volt and the current flowing through it is $1$ ampere,then the resistance $R$ is given by $R = 1 \text{ volt} / 1 \text{ ampere} = 1 \text{ ohm } (\Omega)$.
Thus,$1$ ohm is defined as the resistance of a conductor when a potential difference of $1$ volt applied across its ends causes a current of $1$ ampere to flow through it.