A loose, floppy loop of wire is carrying current I. The loop of wire is placed on a horizontal table in a uniform magnetic field B S perpendicular to the plane of the table. This causes the loop of wire to expand into a circular shape while still lying on the table. In a diagram, show all possible orientations of the current I and magnetic field B S that could cause this to occur. Explain your reasoning.

Let us consider a loose, floppy loop of wire is carrying current I, which placed in a uniform magnetic field B that perpendicular to the plane of loop. This will cause the loop of the wire to expand into a circular shape. In order for this to occur the force must be radially outward, the force acting on a wire carrying current is given by $\overrightarrow{F}=\overrightarrow{I}L\times \overrightarrow{B}$so using right hand rule the force is outward if the current is flowing clockwise and the magnetic field points in to the plane, or if current flows counter clockwise and the magnetic field points outside the plane.

Hence, the force must be radially outward, the force acting on a wire carrying current is given by $\overrightarrow{F}=IL\times \overrightarrow{B}$so using right hand rule the force is outward if the current is flowing clockwise and the magnetic field points in to the plane, or if current flows counter clockwise and the magnetic field points outside the plane.