The percentage increase in magnetic field $(B)$ when the space within a current-carrying solenoid is filled with magnesium (magnetic susceptibility $\chi_{mg} = 1.2 \times 10^{-5}$) is:

$A$ permanent magnet in the shape of a thin cylinder of length $10$ $cm$ has magnetization $M = 10^6$ $A/m$. Calculate the magnetization current $I_M$.

An iron rod of volume $10^{-3} \ m^3$ and relative permeability $1000$ is placed as a core in a solenoid with $10 \ turns/cm$. If a current of $0.5 \ A$ is passed through the solenoid,then the magnetic moment of the rod will be $........... \ Am^2$.

Susceptibility of $Mg$ at $300\, K$ is $1.2 \times 10^{-5}$. The temperature at which susceptibility will be $1.8 \times 10^{-5}$ is......$K$.

$A$ rod of ferromagnetic material with dimensions $10 \, cm \times 0.5 \, cm \times 0.2 \, cm$ is placed in a magnetic field of strength $0.5 \times 10^4 \, Am^{-1}$. As a result,a magnetic moment of $5 \, Am^2$ is produced in the rod. The value of magnetic induction will be.... $T$

What is the magnetisation of a substance?