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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.
State how magnetic susceptibility is different for the three types of magnetic materials, i.e. diamagnetic, paramagnetic and ferromagnetic materials
State two advantages of an electromagnet over a permanent magnet.
Why should the material used for making permanent magnets have high coercivity?
A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane perpendicular to the magnetic meridian. The needle will stay ______.
A tangent galvanometer is connected directly to an ideal battery. If the number of turns in the coil is doubled the deflection will
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.
Figure shows some of the equipotential surfaces of the magnetic scalar potential. Find the magnetic field B at a point in the region.
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.
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.
If the earth's magnetic field has a magnitude 3.4 × 10−5 T at the magnetic equator of the earth, what would be its value at the earth's geomagnetic poles?
A magnetic needle is free to rotate in a vertical plane which makes an angle of 60° with the magnetic meridian. If the needle stays in a direction making an angle of `tan^-1(2sqrt(3))` with the horizontal, what would be the dip at that place?
The magnetometer of the previous problem is used with the same magnet in Tan-B position. Where should the magnet be placed to produce a 37° deflection of the needle?
The combination of two bar magnets makes 10 oscillations per second in an oscillation magnetometer when like poles are tied together and 2 oscillations per second when unlike poles are tied together. Find the ratio of the magnetic moments of the magnets. Neglect any induced magnetism.
Which property of soft iron makes it useful for preparing electromagnet?
A steel wire of length 1 has a magnetic moment m it is then bent into a semicircular arc. The new magnetic moment is
