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प्रश्न
Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.
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उत्तर
| Sr. No. | Paramagnetic | Ferromagnetic |
| 1. | Substances which are weakly attracted by a magnet are called paramagnetic substances. | Substances which are strongly attracted by a magnet are called ferromagnetic substances. |
| 2. | Paramagnetic materials lose their magnetism on removal of the external field and hence cannot be used to make permanent magnets. | Ferromagnetic materials retain some magnetism on removal of the external field and hence can be used to make permanent magnets. |
| 3. | The susceptibility is positive but small. | The susceptibility is positive but very high. |
| 4. | In the absence of an electric field, the net dipole moment is zero. | In the absence of an electric field, the net dipole moment is non-zero. |
| 5. | Aluminium, manganese, chromium and platinum are some examples of paramagnetic substances. | Iron, nickel, cobalt, gadolinium, dysprosium and their alloys are some examples of ferromagnetic substances. |
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संबंधित प्रश्न
Which of the following substances is ductile?
In what way is the behaviour of a diamagnetic material different from that of a paramagnetic, when kept in an external magnetic field?
Show diagrammatically the behaviour of magnetic field lines in the presence of (i) paramagnetic and (ii) diamagnetic substances. How does one explain this distinguishing feature?
The magnetic susceptibility of annealed iron at saturation is 4224. Find the permeability of
annealed iron at saturation. (μ0 = 4Π × 10−7 SI unit)
The susceptibility of a magnetic material is 0·9853. Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.
Explain Curie’s law for a paramagnetic substance.
A tangent galvanometer shows a deflection of 45° when 10 mA of current is passed through it. If the horizontal component of the earth's magnetic field is `B_H = 3.6 xx 10^-5 "T"` and radius of the coil is 10 cm, find the number of turns in the coil.
Choose the correct option:
A rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely. Its period of oscillation is T′, the ratio of T′/T is ______.
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?
A domain in a ferromagnetic substance is in the form of a cube of side 1 µm. If it contains 8 × 1010 atoms and each atomic dipole has a dipole moment of 9 × 10-24 Am2 then the magnetisation of the domain is ______.
For a paramagnetic substance, the magnetic susceptibility is ______.
Magnetization of the sample is ______.
Magnetic material can be easily magnetized if magnetic susceptibility is ______.
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 ____________.
The materials having negative magnetic susceptibility are ____________.
Which graph shows the variation of magnetic susceptibility (`chi`) with magnetizing field (H) for a paramagnetic substance?
Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?
Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?
What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building ‘memory stores’ in a modern computer?
A certain region of space is to be shielded from magnetic fields. Suggest a method.
A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond curie temperature, then it will show ______.
Assertion: The ferromagnetic substance do not obey Curie’s law.
Reason: At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
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?
For a diamagnetic material
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.
A long solenoid has 1000 turns per metre and carries a current of 1 A. It has a soft iron core of µr = 1000. The core is heated beyond the Curie temperature, Tc.
- The H field in the solenoid is (nearly) unchanged but the B field decreases drastically.
- The H and B fields in the solenoid are nearly unchanged.
- The magnetisation in the core reverses direction.
- The magnetisation in the core diminishes by a factor of about 108.
Explain quantitatively the order of magnitude difference between the diamagnetic susceptibility of N2 (~5 × 10–9) (at STP) and Cu (~10–5).
From molecular view point, discuss the temperature dependence of susceptibility for diamagnetism, paramagnetism and ferromagnetism.
Which of the following has a permeability less than that of free space?
The relative magnetic permeability of a substance X is slightly less than unity and that of substance Y is slightly more than unity, then ______.
Explain ferromagnetism on the basis of the domain theory.
Magnetic susceptibility of a diamagnetic substance ______.
Match List-I with List-II.
| List-I (Material) | List-II (Susceptibility) | ||
| A. | Diamagnetic | I. | χ = 0 |
| B. | Ferromagnetic | II. | 0 > χ ≥ −1 |
| C. | Paramagnetic | III. | χ >> 1 |
| D. | Non-magnetic | IV. | 0 < χ < ε |
Choose the correct answer from the options given below:
Which substances are strongly magnetised in the direction of the magnetising field?
On what basis are materials broadly classified into diamagnetic, paramagnetic, and ferromagnetic groups?
What is the susceptibility of diamagnetic substances?
How do paramagnetic substances respond to a magnetic field?
Which list contains only examples of paramagnetic substances?
How does the magnetic susceptibility of a paramagnetic material vary with its absolute temperature under Curie's Law?
Which mathematical relation expresses Curie's Law for paramagnetic substances?
What happens to paramagnetic substances on cooling at the Curie temperature?
What causes the magnetic behaviour of ferromagnetic substances?
How are the tiny domains oriented in an unmagnetised ferromagnetic specimen?
