Hysteresis, Soft Iron vs Steel & Shielding
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?
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Answer: (b)
- A permanent magnet must keep its magnetism (large retentivity) and resist demagnetisation (large coercivity).
- A transformer core needs small coercivity and a narrow loop for low hysteresis loss. That rules out options (a) and (d).
- So the answer is (b) P: large retentivity, large coercivity.