Question

Magnetic susceptibility for paramagnetic and diamagnetic materials is respectively
A) Small, positive and small, positive
B) Large, positive and small, negative
C) Small, positive and small, negative
D) Large, negative and large positive

Answer 1

Hint: The magnetic susceptibility of a material is defined as the ratio of magnetization produced in a material to the magnetic field intensity. Diamagnetic material creates an induced magnetic field and is repelled by the applied magnetic field.

Complete step by step solution:
Let’s analyze this question options wise:
A) SMALL, POSITIVE AND SMALL, POSITIVE:- As diamagnetic substances are repelled by the magnetic field they have negative susceptibility. Hence, this option is incorrect.
B) LARGE, POSITIVE AND SMALL, NEGATIVE:- The atoms or molecules of the paramagnetic substance have net orbital or spin magnetic moments that are capable of being aligned in the direction of the applied field. Therefore, they have a positive (but small) susceptibility and a relative permeability slightly over one. Hence, this option is wrong.
C) SMALL, POSITIVE AND SMALL NEGATIVE:- paramagnetic substances are attracted by the magnetic field so they have positive susceptibility and diamagnetic are repelled by the magnetic field so the susceptibility is negative. Thus, this option is correct.
D) LARGE NEGATIVE AND LARGE POSITIVE:- Diamagnetic materials have a weak, negative susceptibility to magnetic fields. Paramagnetic properties are due to the presence of some unpaired electrons. Hence this option is also wrong.

Magnetic susceptibility for paramagnetic small positive and diamagnetic materials is a small negative. So, option (C) is correct.

Additional information:
The magnetic susceptibility can be defined as the ratio magnetism and magnetic field strength. Paramagnetism and diamagnetism can be defined as the magnetic susceptibility. If magnetic susceptibility is less than zero then it is anti-aligned then the material is diamagnetic. If the magnetic susceptibility is more than zero then it is aligned and the material is paramagnetic.

Note:
If χ is positive, a material can be paramagnetic. In this case, the magnetic field in the material is strengthened by the induced magnetization. Alternatively, if χ is negative, the material is diamagnetic. In this case, the magnetic field in the material is weakened by the induced magnetization.
Diamagnetic substances are those in which the net magnetic moment of atoms is zero.
- The susceptibility has a low negative value.
- Susceptibility is independent of temperature.
- The relative permeability is slightly less than one.

Properties of Paramagnetic Materials:
- The substances are weakly attracted by the magnetic field.
- Magnetic susceptibility is small and positive.
- The relative permeability is slightly greater than 1.