A straight bar magnet of length 10 cm is placed horizontally on a sheet of paper with…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A straight bar magnet of length 10 cm is placed horizontally on a sheet of paper with its North pole on the left and South pole on the right. A student is asked to map the magnetic field surrounding the magnet.
(a) Sketch on the paper at least six representative external magnetic field lines around the magnet and clearly indicate their directions with arrows.
(b) Describe, in words, why the magnetic field lines you drew neither start nor end on the surface of the magnet but instead form continuous closed loops that pass through the interior of the magnet.
(c) The magnet is broken cleanly at its midpoint, producing two shorter pieces. State the polarity that appears at each new end and explain how the field‐line pattern around one of the broken pieces would compare with that of the original whole magnet.
(d) Along the line extending outward from the North pole (the axial line), qualitatively discuss how the magnitude of the magnetic field changes with increasing distance from the pole. Justify your answer with reference to the geometry of the field lines.