Three identical small cubes made respectively of copper
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
Three identical small cubes made respectively of copper, oxygen (solid) and nickel are simultaneously released from rest midway between the pole pieces of a powerful electromagnet that produces a strongly non-uniform magnetic field in the horizontal direction.
(i) Rank the cubes in the order in which they reach the stronger field region, starting with the first to arrive. Give proper reasoning for your ranking.
(ii) For each cube, state qualitatively whether the magnetisation M is positive, negative or approximately zero when the external field is switched on, and justify your answer.
(iii) Sketch (no numerical scales needed) separate curves showing the expected variation of M with the applied field H for copper, oxygen and nickel on the same set of axes.
(iv) Describe a simple laboratory procedure, using only a strong magnetic field and mechanical handling, by which the nickel cube could be converted into a weak permanent magnet.