MCQ
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
    $\frac{32}{3}\text{Am}^{-1}$
  • $\frac{2}{3}\text{Am}^{-1}$
  • C
    $6\text{Am}^{-1}$
  • D
    $2.4\text{Am}^{-1}.$

Answer

Correct option: B.
$\frac{2}{3}\text{Am}^{-1}$

From the Curie’s law explains, $\text{I}\propto\frac{\text{B}}{\text{T}}$
Here, $B$ is magnetic field induction, $I$ is the intensity of magnetisation and $T$ is absolute temperature.
$\Rightarrow\ \Big(\frac{\text{I}_2}{\text{I}_1}\Big)=\Big(\frac{\text{B}_2}{\text{B}_1}\Big)\times\Big(\frac{\text{T}_1}{\text{T}_2}\Big)$
Given,
$I _1=8 Am ^{-1}, B_1=0.6 T, T _1=4 K, B _2=0.2 T, T _2=16 K, I _2=?$
By putting values in equation $…(i),$ we have,
$\text{I}_2=\Big(\frac{2}{3}\Big)\text{Am}^{-1}.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

In the circuit shown in the adjoining figure, the current between B and D is zero, the unknown resistance is of
According to classical theory, path of electron in Rutherford model :
In Young’s double slit experiment, the distance between the two slits is made half, then the fringe width will become
At the magnetic north pole of the earth, the value of the horizontal component of earth’s magnetic field and angle of dip are respectively:
In the given circuit, a charge of $+80\, \mu C$ is given to the upper plate of the $4\,\mu F$ capacitor. Then in the steady state, the charge on the upper plate of the $3\,\mu F$ capacitor is.....$\mu C$
Assertion : A laser beam 0.2 W power can drill holes through a metal sheet, whereas 1000 W torch-light cannot.
Reason : The frequency of laser light is much higher then that of torch light.
A thin rod is bent in the shape of a small circle of radius $'r'$. If the charge per unit length of the rod is $'\sigma ',$ and if the circle is rotated about its axis at the rate of $'n'$ rotation per second, the magnetic induction at a point on the axis at a large distance $'y'$ from the centre is
The photoelectric threshold of Tungsten is $2300\; \mathring A$. The energy of the electrons ejected from the surface by ultraviolet light of wavelength $1800\; \mathring A$ is $.............\,eV$
In a Young's double slit experiment, a student observes $8$ fringes in a certain segment of screen when a monochromatic light of $600\,nm$ wavelength is used. If the wavelength of light is changed to $400\,nm$, then the number of fringes he would observe in the same region of the screen is:
Two copper balls, each weighing 10g are kept in air 10 cm apart. If one electron from every $10^6$ atoms is transferred from one ball to the other, the coulomb force between them is (atomic weight of copper is 63.5)