Advertisements
Advertisements
प्रश्न
A paramagnetic gas has 2.0 × 1026 atoms/m with atomic magnetic dipole moment of 1.5 × 10−23 A m2 each. The gas is at 27°C.
- Find the maximum magnetization intensity of this sample.
- If the gas in this problem is kept in a uniform magnetic field of 3 T, is it possible to achieve saturation magnetization? Why?
Advertisements
उत्तर
Data: `"N"/"V" = 2.0 xx 10^26` atoms/m3,
µ = 1.5 × 10-23 Am2, T = 27 + 273 = 300 K, B = 3 T, kB = 1.38 × 10-23 J/K, 1 eV = 1.6 × 10-19 J
(a) The maximum magnetization of the material,
`"M"_"z" = "N"/"V" mu = (2.0 xx 10^26)(1.5 xx 10^-23)`
= 3 × 103 A/m
(b) The maximum orientation energy per atom is
`upsilon_"max" = - mu"B" cos 180^circ = mu"B"`
`= (1.5 xx 10^-23)(3) = (4.5 xx 10^-23)/(1.6 xx 10^-19)`
= 2.8 × 10-4 eV
The average thermal energy of each atom,
E = `3/2 "k"_"B" "T"`
where kB is the Botzmann constant.
∴ E = 1.5(1.38 × 10-23)(300)
= 6.21 × 10-21 J = `(6.21 xx 10^-21)/(1.6 xx 10^-19)`
= 3.9 × 10-2 eV
Since the thermal energy of randomization is about two orders of magnitude greater than the magnetic potential energy of orientation, saturation magnetization will not be achieved at 300 K.
APPEARS IN
संबंधित प्रश्न
Give any ‘two’ points of differences between diamagnetic and ferromagnetic substances.
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?
A meter gauge train is heading north with speed 54 km/hr in earth's magnetic field 3 x 10-4T. The e.m.f. induced across the axle joining the wheels is ..........
(a) 0.45 mV
(b) 4.5 mV
(c) 45 mV
(d) 450 m V
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 − 2.6 × 10−5. Identify the type of magnetic material and state its two properties.
The relative magnetic permeability of a magnetic material is 800. Identify the nature of magnetic material and state its two properties.
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:
Two substances A and B have their relative permeability slightly greater and slightly less than 1 respectively. What do you conclude about A and B as far as their magnetic materials are concerned?
Identify the following magnetic materials :
Which of the following statements is correct for diamagnetic materials?
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?
What happens to a ferromagnetic material when its temperature increases above curie temperature?
Answer in brief.
Discuss the Curie law for paramagnetic material.
A rod of magnetic material of cross-section 0.25 cm2 is placed in a magnetizing field of intensity 4000 A/m-1. The magnetic flux passing through the rod is 25 × 10-6 Wb. Find out
(a) relative permeability
(b) magnetic susceptibility and
(c) magnetisation of the rod.
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 ______.
The susceptibility of a magnetic material is positive and small. The material is ______.
All atoms of a magnetic substance have a resultant magnetic moment even in absence of external magnetic field. The substance is ______.
Magnetization of the sample is ______.
If a magnetic field is applied to a liquid in one arm of a narrow U-tube, the liquid level in that arm is lowered. The liquid in U-tube arm is ______.
The materials having negative magnetic susceptibility are ____________.
The product of magnetic susceptibility (`chi`) and absolute temperature (T) is constant for a ____________.
A small quantity of paramagnetic liquid is taken in a watch - glass and kept on two dissimilar magnetic poles. The liquid ____________.
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 ____________.
The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?
Why is diamagnetism, in contrast, almost independent of temperature?
Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?
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?
Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve 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?
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 ______.
Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called ______.
For a diamagnetic material
Most of the substance show which of the magnetic property:-
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 ______.
A permanent magnet in the shape of a thin cylinder of length 10 cm has M = 106 A/m. Calculate the magnetisation current IM.
From molecular view point, discuss the temperature dependence of susceptibility for diamagnetism, paramagnetism and ferromagnetism.
If the magnetizing field on a ferromagnetic material is increased, its permeability ______.
An ammeter of resistance R gives a full-scale deflection when a current of 2 A passes through it. If it is measured with a maximum current of 10 A, the required shunt is ______.
Which of the following cannot modify an external magnetic field as shown in the figure?
What is magnetic hysterisis?
Explain ferromagnetism on the basis of the domain theory.
Explain the origin of paramagnetism on the basis of atomic structure.
