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प्रश्न
Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?
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उत्तर
The permeability of a ferromagnetic material is always greater than one. Hence, magnetic field lines are always nearly normal to the surface of such materials at every point. The proof of this fact is based on the boundary conditions of the magnetic fields at the interface of two media.
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संबंधित प्रश्न
Which of the following substances is ductile?
Out of the two magnetic materials, 'A' has relative permeability slightly greater than unity while 'B' has less than unity. Identify the nature of the materials 'A' and 'B'. Will their susceptibilities be positive or negative?
Choose the correct option:
A magnetising field of 360 Am−1 produces a magnetic flux density (B) = 0.6T in a ferromagnetic material. What is its permeability in Tm A−1?
There are three needles 'N1', 'N2' and 'N3' made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. When a magnet is brought close to them, then it will ____________.
A domain in a ferromagnetic substance is in the form of a cube of side length 1 µm. If it contains 6 x 1010 atoms and each atomic dipole has a dipole moment of 7 x 10-24 Am2, then magnetization of the domain is ____________.
A short bar magnet has a magnetic moment of 0.48 J T−1. Give the direction and magnitude of the magnetic field produced by the magnet at a distance of 10 cm from the centre of the magnet on
- the axis,
- the equatorial lines (normal bisector) of the magnet.
Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 103 Am–1. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is ______.
Which of the following property shows the property of ferromagnetic substances?
A hydrogen atom is paramagnetic. A hydrogen molecule is
The universal property of all substances is ______.
According to the Atomic theory, on heating a magnet, the thermal energy of the elementary magnet ______
A paramagnetic sample shows a net magnetisation of 8 Am–1 when placed in an external magnetic field of 0.6 T at a temperature of 4 K. When the same sample is placed in an external magnetic field of 0.2 T at a temperature of 16 K, the magnetisation will be ______.
S is the surface of a lump of magnetic material.
- Lines of B are necessarily continuous across S.
- Some lines of B must be discontinuous across S.
- Lines of H are necessarily continuous across S.
- Lines of H cannot all be continuous across S.
From molecular view point, discuss the temperature dependence of susceptibility for diamagnetism, paramagnetism and ferromagnetism.
A uniform magnetic field gets modified as shown in figure when two specimens A and B are placed in it.
 |
 |
| (a) | (b) |
- Identify the specimen A and B.
- How is the magnetic susceptibility of specimen A different from that of specimen B?
Which of the following cannot modify an external magnetic field as shown in the figure?
Explain the meaning of the following statement:
Curie temperature for soft iron is 770°C.
