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प्रश्न
The desirable properties for making permanent magnets are _________________ .
पर्याय
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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संबंधित प्रश्न
State any two advantages of electromagnets over permanent magnets.
Write two characteristics of a material used for making permanent magnets ?
Why should the material used for making permanent magnets have high coercivity?
If the current is doubled, the deflection is also doubled in
Consider the situation of the previous problem. The directions of the magnetic field due to the dipole are opposite at
(a) P1 and P2
(b) Q1 and Q2
(c) P1 and Q1
(d) P2 and Q2
Two long bare magnets are placed with their axes coinciding in such a way that the north pole of the first magnet is 2.0 cm from the south pole of the second. If both the magnets have a pole strength of 10 Am, find the force exerted by one magnet of the other.
A uniform magnetic field of `0.20 xx 10^-3 "T"` exists in the space. Find the change in the magnetic scalar potential as one moves through 50 cm along the field.
A bar magnet has a length of 8 cm. The magnetic field at a point at a distance 3 cm from the centre in the broadside-on position is found to be `4 xx 10^-6 "T"`.Find the pole strength of the magnet.
A magnetic dipole of magnetic moment `1.44 "A m"^2`is placed horizontally with the north pole pointing towards north. Find the position of the neutral point if the horizontal component of the earth's magnetic field is 18 μT.
Do permeability and relative permeability have the same dimensions?
The coercive force for a certain permanent magnet is 4.0 × 104 A m−1. This magnet is placed inside a long solenoid of 40 turns/cm and a current is passed in the solenoid to demagnetise it completely. Find the current.
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.
Soft iron is used to make the core of the transformer because of its ______.
The relation b/w magnetic susceptibility xm and relativ~ permeability µr is
A wire of length 2 m carrier of lamp is bend to form a circle. The magnetic moment of a coil is :-
Which magnetic properties are desirable for making a permanent magnet?
