Here's why:

* Magnetomotive force (MMF) is the driving force behind the creation of a magnetic field. It's analogous to electromotive force (EMF) in an electrical circuit.

* Ampere turns are a unit of measurement for MMF. One ampere turn is the MMF produced by a single loop of wire carrying one ampere of current.

* MMF = NI, where:

* N is the number of turns in a coil.

* I is the current flowing through the coil.

Therefore, the product of the number of turns and the current (NI) gives you the magnetomotive force, which is measured in ampere turns.