Pole Strength

—In magnetism, the force exerted by a magnetic pole at a distance upon another magnet. A unit magnetic pole is a pole of such strength as to repel with a force of one dyne an equal and similar pole placed at a distance of one centimeter from it. $ A magnet’s pole strength can be estimated by measuring the force with which it attracts or - repels another pole. the force being equal to the product of the two polar strengths. If M represents the strength of one pole and M+ the strength of the other similarly magnetized, the force of their repulsion will be M times M?. This force f varies inversely as the square of the distance, and may be expre ed by the following formula: M M? I where d equals the distance between the poles.