The susceptibility of tungsten is $6.8 \times 10^{-5}$ at temperature $300 \ K$. The susceptibility at temperature $400 \ K$ is

Explain diamagnetism and diamagnetic substances.

Which of the following statements is true in respect of diamagnetic substances?

If the magnetic dipole moment of an atom of diamagnetic material,paramagnetic material,and ferromagnetic material are denoted by $\mu_d, \mu_p, \mu_f$ respectively,then:

Steel is preferred over soft iron for permanent magnets because

$A$ sample of a paramagnetic salt containing $3 \times 10^{24}$ atomic dipoles each of dipole moment $2 \times 10^{-23} \text{ A-m}^2$ is subjected to a uniform magnetic field of $880 \text{ mT}$ and cooled to a temperature of $3.5 \text{ K}$. The degree of magnetic saturation achieved is $10 \%$. If the sample is subjected to a magnetic field of $990 \text{ mT}$ and cooled to a temperature of $2.1 \text{ K}$, then the total dipole moment of the sample is (in $\text{ A-m}^2$)