A strip‐wound ferromagnetic alloy is studied to determine how its magnetic properties…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A strip‐wound ferromagnetic alloy is studied to determine how its magnetic properties vary with temperature. For a fixed magnetic field intensity H=4.0×103Am−1, the measured relative permeability μr at several temperatures is recorded.
Temperature T (∘C): 20, 100, 200, 300, 400, 500
Relative permeability μr: 3400, 3000, 1800, 600, 1.2, 1.0
(a) Describe the overall trend shown by the data as temperature increases from 20 ∘C to 500 ∘C.
(b) Using atomic‐level reasoning, explain why the relative permeability decreases sharply as the temperature approaches 400 ∘C and above.
(c) Estimate the temperature (from the given list) at which the magnetic flux density inside the sample is effectively the same as that in free space for the stated value of H, and justify your choice.