Final answer:
The magnetic effects of a bar magnet are concentrated near the ends, or poles, where the magnetic field is stronger.
Step-by-step explanation:
The magnetic effects of a bar magnet are most concentrated near the ends of the magnet, which are known as the poles. The magnetic field lines exit from the north pole of the magnet and enter at the south pole, indicating the direction of the magnetic field. As evidenced by the density of the magnetic field lines, which are closer together at the ends, the magnetic field is stronger at the poles than in the middle. It's important to note that while the magnetic field is stronger at the poles, it is not correct to say it's stronger at the north pole over the south pole; both poles have equivalent strength in a bar magnet.