Three small samples of common materials are placed two centimeters from the north…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
Three small samples of common materials are placed two centimeters from the north pole of a strong permanent bar magnet on a low-friction surface. The samples are
• an iron nail
• a fragment cut from an aluminum soda can
• a small pellet of pure bismuth
When released from rest, the iron nail accelerates toward the magnet and sticks to the pole. The aluminum fragment drifts slowly toward the magnet but falls away immediately once the magnet is removed. The bismuth pellet drifts slightly away from the magnet and comes to rest a few millimeters farther from the pole.
Use these observations to analyze the magnetic behavior of the three samples.
(a) Define ferromagnetic, paramagnetic, and diamagnetic behavior in terms of the interaction of a material with an external magnetic field.
(b) For each of the three samples, state the type of magnetic behavior it exhibits and cite the specific experimental observation that supports your choice.
(c) Identify which sample, if any, would retain a measurable magnetization after the external field is removed. Explain your answer briefly in terms of the alignment of internal magnetic domains or induced dipoles.