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General
Easy
Question
The figure illustrate how B, the flux density inside a sample of unmagnetised ferromagnetic material varies with B0, the magnetic flux density in which the sample is kept. For the sample to be suitable for making a permanent magnet
- OQ should be large, OR should be small
- OQ and OR should both be large
- OQ should be small and OR should be large
- OQ and OR should both be small
The correct answer is: OQ and OR should both be large
In the given figure OQ refers to retentivity while OR refers to corecivity, for permanents both retentivity and corecivity should be high.
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