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प्रश्न
The desirable properties for making permanent magnets are _________________ .
विकल्प
high retentivity and high coercive force
high retentivity and low coercive force
low retentivity and high coercive force
low retentivity and low coercive force
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उत्तर
high retentivity and high coercive force
Permanent magnets should have high retentivity so that the magnet is strong and high coercive force, so that magnetisation is not erased by stary magnetic fields, temperature change or due to rough handling etc.
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