\begin{definition}[Definition:Ampere (Unit)]
The '''ampere''' is the SI base unit of electric current.
It is defined as being:
:The constant current which will produce a force of attraction whose value is $2 \times 10^{–7}$ newtons per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum.
This arises from Ampère's Force Law, which states that such an attractive force exists.
\end{definition}