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:

Needles $N_{1}$,$N_{2}$,and $N_{3}$ are made of a ferromagnetic,a paramagnetic,and a diamagnetic substance,respectively. $A$ magnet when brought close to them will

Materials suitable for permanent magnets must have which of the following properties?

What is the value of magnetic susceptibility $\chi$ for:
$(i)$ Paramagnetic material
$(ii)$ Diamagnetic materials

Ferromagnetic materials used in a transformer must have

$A$ sample of paramagnetic salt contains $2 \times 10^{24}$ atomic dipoles each of dipole moment $1.5 \times 10^{-23} \text{ J T}^{-1}$. The sample is placed under a homogeneous magnetic field of $0.6 \text{ T}$ and cooled to a temperature of $4.2 \text{ K}$. The degree of magnetic saturation achieved is $20 \%$. What is the total dipole moment of the sample for a magnetic field of $0.9 \text{ T}$ and a temperature of $2.8 \text{ K}$ (in $\text{ J T}^{-1}$)?