Question

Write two properties of paramagnetic substances.

Hint:

Paramagnetic substances = Weakly attracted by magnetic fields, and they do not retain magnetization after the field is removed.

Answer 1

Paramagnetic substances are materials that are weakly attracted by an external magnetic field and do not retain magnetic properties once the external field is removed. The two key properties of paramagnetic substances are:
1. Weak Attraction to Magnetic Fields: Paramagnetic substances are weakly attracted to external magnetic fields. This occurs because, in these materials, the magnetic moments of individual atoms or molecules do not completely cancel out. However, the attraction is much weaker than that in ferromagnetic materials. The degree of magnetization is proportional to the applied magnetic field, following the relation \(M = \chi H\), where \(\chi\) is the magnetic susceptibility (which is positive for paramagnetic substances).
2. No Retention of Magnetization: Unlike ferromagnetic materials, paramagnetic substances do not retain magnetization once the external magnetic field is removed. In these materials, the magnetic moments tend to align with the magnetic field when applied, but random thermal motion disrupts this alignment once the field is removed. This lack of residual magnetization is a key distinguishing feature of paramagnetism.
Other characteristics of paramagnetic substances include their temperature-dependent behavior. As the temperature increases, the thermal agitation of atoms or molecules increases, leading to a decrease in the alignment of the magnetic moments and, consequently, a reduction in the magnetization.
In summary, the two key properties of paramagnetic substances are their weak attraction to magnetic fields and the absence of permanent magnetization.