Question

Four compasses are placed around a wire, as shown.

A long wire that is vertical and standing on a steel plate. There are 4 compasses surrounding it and all of the needles are pointing in the same direction, west.

The wire is then connected to a battery so that a current flows down the wire.

How will the compasses point once the current is flowing?

A long wire that is vertical and standing on a steel plate. There are 4 compasses surrounding it and all of the needles are pointing in the same direction, west.
A long wire that is vertical and standing on a steel plate. There are 4 compasses surrounding it and all of the needles are pointing in the same direction, east.
A long wire that is vertical and standing on a steel plate. There are 4 compasses surrounding it and all of the needles are pointing clockwise.
A long wire that is vertical and standing on a steel plate. There are 4 compasses surrounding it and all of the needles are pointing counterclockwise.
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Answer 1

All the needles will point clockwise.

Reason: a downward current produces circular magnetic field lines around the wire that run clockwise when seen from above (right‑hand rule), so the compasses align tangentially in the clockwise direction.