Question

The relative permeability of a material A is slightly more than unity while that of a material B is slightly less than unity. Which of the following statement relating to the materials A and B is correct?
1. Material A is diamagnetic and B paramagnetic.
2. Both the materials A and B are ferromagnetic
3. Both the materials A and B are paramagnetic
4. Material A is paramagnetic and B diamagnetic

Answer 1

Correct Answer - Option 4 : Material A is paramagnetic and B diamagnetic

Explanation:

Material	Magnetic Susceptibility (Xm­)	Relative Permeability (Km = 1 + Xm)	Magnetic Permeability (μm = Kmμ0)
Diamagnetic	-10-5 to -10-9	< 1	μm < μ0
Paramagnetic	10-5 to 10-3	> 1	μm > μ0
Ferromagnetic	≫ 1	≫ 1	μm ≫ μ0

 

From the above table, we can consider that material A Paramagnetic and material B is Diamagnetic.

Paramagnetic Substances: The substances which are weakly magnetized when placed in an external magnetic field, in the same direction of the applied field are called paramagnetic substances.

Example: Sodium, aluminum, calcium, manganese, platinum

Properties:

• These substances are attracted by a magnet
• Atomic orbitals of these substances are partially filled
• It develops weak magnetization in the direction of the applied magnetic field
• After removing the magnetizing field, it loses its magnetization
• When placed in a non-uniform magnetic field, it tends to move from weaker to stronger regions of the magnetic field
• When placed in a uniform magnetic field, it aligns itself in the direction of the magnetic field
• Magnetic susceptibility is a small positive value
• Relative permeability is close to one and always greater than 1
• Magnetic permeability is slightly more compared to free space