تسجيل الدخول

تسجيل

Polarity

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-301

2025-11-26

418

Lay a bar magnet upon table covered with small nails, and then lift it by the middle. It will be found that the nails cling to the magnet, the greater number being near the ends, as in Fig. 1. The two points near the ends where the most nails cling indicate the position of the poles of the magnet.

FIG.1

Suspend the bar magnet by a thread attached to its middle point, and after swinging back and forth for a time it will finally come to rest in a direction that is nearly north and south.

It has been agreed to call the end which points to the magnetic north the + or north pole and the other the - or south pole. The strictly correct names would be north-seeking pole and south-seeking pole. A body with such poles is said to be polarized, and to possess polarity.