Answer:
a.Magnetic field lines are closed curves leaving from North pole and entering the South pole when you follow them on the outside the magnet. A compass, which is a small magnet itself, lines up parallel to the magnetic field lines at the point it is placed.
b.Magnetic field lines are defined to have the direction that a small compass points when placed at a location. (a) If small compasses are used to map the magnetic field around a bar magnet, they will point in the directions shown: away from the north pole of the magnet, toward the south pole of the magnet.
Explanation:
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