PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
Four identical cubes of different, unlabeled materials (A, B, C, and D) are placed at rest on a smooth horizontal surface halfway between the opposite poles of a large electromagnet that produces a uniform horizontal magnetic field. When the field is turned on, the following motions are observed:
• Cube A accelerates quickly into the gap between the poles and remains there after the field is turned off.
• Cube B drifts slowly into the gap but slides back to its original position once the field is removed.
• Cube C does not move.
• Cube D drifts slowly away from the gap while the field is on and returns to rest when the field is off.
(a) For each cube, state the type of magnetic behavior it exhibits. Support each classification with the corresponding observed motion.
(b) Rank the four cubes from greatest to least in terms of the magnitude of the magnetization induced while the field is on. Provide a brief justification.
(c) Describe an experimental procedure—using only the electromagnet, a sensitive balance, and a ruler—that would allow a quantitative comparison of the relative permeabilities of cubes B and D.