Where are the strongest magnetic field lines around a bar magnet found?

Where are the strongest magnetic field lines around a bar magnet found?

• A. The field lines exit at both poles but are weakest at the poles.
• B. The field lines are strongest at the poles and form closed loops from north to south outside.
• C. The field is uniform along the length of the magnet.
• D. There are no magnetic field lines outside the magnet.

Answer: (B)

Magnetic field strength is shown by how densely the field lines are packed. Around a bar magnet the lines are most dense at the ends, the poles, so the field is strongest there. Outside the magnet, the lines leave the north pole and curve around to enter the south pole, forming closed loops that go from north to south outside (and then from south to north inside). As you move away, the lines spread out, so the field becomes weaker. So the strongest field is at the poles, with lines forming continuous loops from north to south outside.

Magnetic field strength is shown by how densely the field lines are packed. Around a bar magnet the lines are most dense at the ends, the poles, so the field is strongest there. Outside the magnet, the lines leave the north pole and curve around to enter the south pole, forming closed loops that go from north to south outside (and then from south to north inside). As you move away, the lines spread out, so the field becomes weaker. So the strongest field is at the poles, with lines forming continuous loops from north to south outside.