Advertisements
Advertisements
प्रश्न
Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
Advertisements
उत्तर
Owing to the random thermal motion of the molecules, the alignments of dipoles get disrupted at high temperatures. On cooling, this disruption is reduced. Hence, a paramagnetic sample displays greater magnetisation when cooled.
संबंधित प्रश्न
Give any ‘two’ points of differences between diamagnetic and ferromagnetic substances.
The susceptibility of magnesium at 200 K is 1.8 x 10-5. At what temperature will the susceptibility decrease by 6 x 10-6?
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?
Explain Curie’s law for a paramagnetic substance.
Draw magnetic field line when a (i) diamagnetic, (ii) paramagnetic substance is placed in an external magnetic field. Which magnetic property distinguishes this behaviour of the field line due to the substances?
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.
The magnetic susceptibility of platinum is 0.0001. It's relative permeability is:
Answer the following question.
Write three points of differences between para-, dia- and ferromagnetic materials, giving one example for each.
Identify the following magnetic materials :
Magnetization of the sample is ______.
Relative permittivity and permeability of a material are `epsilon_"r"` and `µ_"r"` respectively. Which of the following values of these quantities are allowed for a diamagnetic material?
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 ____________.
Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet.
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?
For a diamagnetic material
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 ______.
Explain the meaning of the following statement:
Curie temperature for soft iron is 770°C.
