A wire 0.15 m long carries 8 A at right angles to a field of 0.45 T.

A wire with a current in a magnetic field feels a force $F = BIL\sin\theta$, where $\theta$ is the angle between the wire and the field. It is largest ($F = BIL$) at right angles, and zero along the field. Fleming's left-hand rule: forefinger for the field, middle finger for the current, thumb for the force.