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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
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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संबंधित प्रश्न
State any two advantages of electromagnets over permanent magnets.
What are permanent magnets? Give one example ?
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A bar magnet takes π/10 second the complete one oscillation in an oscillation magnetometer. The moment of inertia of the magnet about the axis of rotation is 1.2 × 10−4 kg m2 and the earth's horizontal magnetic field is 30 μT. Find the magnetic moment of the magnet.
A bar magnet makes 40 oscillations per minute in an oscillation magnetometer. An identical magnet is demagnetized completely and is placed over the magnet in the magnetometer. Find the time taken for 40 oscillations by this combination. Neglect any induced magnetism.
Choose the correct option:
Soft iron is used to make the core of the transformer because of its ______.
Which property of soft iron makes it useful for preparing electromagnet?
What should be retentivity and coercivity of permanent magnet?
