What does the magnetic susceptibility of a material show?

An iron rod of volume $10^{-4} \, m^3$ and relative permeability $1000$ is placed inside a long solenoid wound with $5 \, \text{turns/cm}$. If a current of $0.5 \, A$ is passed through the solenoid, then the magnetic moment of the rod is .... $A m^2$.

$A$ substance has a mass of $0.075 \, kg$ and a density of $7500 \, kg/m^3$. If its magnetic dipole moment is $8 \times 10^{-7} \, A \cdot m^2$,what is its magnetization in $A/m$?

The magnetic moment of a sample of $2 \text{ g}$ is $8 \times 10^{-7} \text{ Am}^2$. If its density is $4 \text{ g/cm}^3$,then the magnetization of the sample in $\text{Am}^{-1}$ is:

The magnetic moment produced in a sample of $2 \text{ g}$ is $8 \times 10^{-7} \text{ A} \cdot \text{m}^2$. If its density is $4 \text{ g/cm}^3$, then the magnetization of the sample is: (in $\text{ A/m}$)

What is the magnetic susceptibility of a medium if its relative permeability is $0.85$?