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प्रश्न
Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet.
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उत्तर
The hysteresis curve (B-H curve) of a ferromagnetic material is shown in the following figure.

It can be observed from the given curve that magnetisation persists even when the external field is removed. This reflects the irreversibility of a ferromagnet.
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