an B position. The compass box alone is rotated so that the (90-90) line is parallel to the arm of the magnetometer. Then the magnetometer as a whole is rotated so that the pointer reads (0-0). The magnet is placed horizontally, but perpendicular to the arm of magnetometer. Repeat the whole process as before, to get a second average value of m/BH using equation (8), which is combined into an overall average with the first.
To find pole strength P