A -long cylindrical bar magnet has its North pole at and its South pole at along a…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A
10cm-long cylindrical bar magnet has its North pole at x=0 and its South pole at x=10cm along a horizontal axis. The magnet is sawed transversely at x=3cm, producing two fragments: fragment 1 (0≤x≤3cm) and fragment 2 (3cm<x≤10cm). The two fragments are then placed back on the axis in their original order, with a 1mm air gap between them.
(a) Label the magnetic poles that exist at each of the four exposed end faces after the cut. Give your reasoning.
(b) Sketch the approximate direction of the external magnetic field lines in the region just outside each end face and in the narrow air gap.
(c) Considering the two fragments together as a system, state whether the overall magnetic dipole moment of the system has changed in magnitude, direction, or neither. Justify your answer.
(d) The fragments are now slid apart so that the air gap widens to 5cm. Predict qualitatively how the external magnetic field in the midway region between the two original end faces will change, and explain the physical cause of that change.