Step 1 (Formula / Governing Law & Given Data): [0.5 Mark]
Magnetic susceptibility ($\chi_m$) is a dimensionless measure of how much a material becomes magnetized in an applied magnetic field. It is defined by the relation:
$$\chi_m = \frac{M}{H}$$where $M$ is the magnetization induced in the material and $H$ is the applied magnetic field intensity.
The relation between relative magnetic permeability ($\mu_r$) and magnetic susceptibility ($\chi_m$) is given by:
$$\mu_r = 1 + \chi_m$$Step 2 (Step-by-Step Mathematical Working): [0.5 Mark]
For diamagnetic materials:
- When placed in an external magnetic field, an extremely weak magnetic dipole moment is induced in a direction opposite to the applied field ($M \propto -H$).
- Consequently, the value of relative permeability is slightly less than unity:
Rearranging the equation $\chi_m = \mu_r - 1$ gives:
$$-1 \le \chi_m < 0$$Thus, the value of magnetic susceptibility $\chi_m$ is small and negative (typically of the order of $10^{-5}$ to $10^{-9}$ and independent of temperature).
Step 3 (Final Concluded Answer):