The magnetic field produced by two parallel wires is indicated by the x's (into the page) and dots (out of the page) in the accompanying picture. The currents in the wires must be a) leftward in the top wire and rightward in the bottom wire b) leftward in the top wire and leftward in the bottom wire . c) rightward in the top wire and rightward in the bottom wire d) rightward in the top wire and leftward in the bottom wire

have two possibilities a and d

Explanation:

The direction of the magnetic field in a wire that carries a current can be found by the rule of the right hand where the thumb points in the direction of the current and the fingers in the direction of the magnetic field. In this case of a wire the magnetic field is circular around the wire.

As a consequence of the above, on one side of the wire the field is outgoing and on the other incoming side. Specifically, if the upper wire carries a current to the right, the field below it is incoming (points), if the cable below it carries the current in the same direction, the field above is outgoing (crosses), so the net field would be zero, for the two fields to add they must be different from zero the lower wire must carry the current in the opposite direction to the upper wire

the review the answers, we only have two possibilities a and d

in the case of the response to the magnetic field is outgoing (curses

in the case of the response d the magnetic field is incoming (points)

magnityde and direction