Question

Consider the following statements:

1. SI unit of permeability is Am^-1.

2. Platinum, aluminum, and chromium are three diamagnetic materials.

3. Diamagnetic materials have a permeability of more than 1.

4. SI unit of magnetization isTesla.

Which of the following statement is/are CORRECT?

1. only 1) and 2) are correct
2. only 3) and 4) are correct
3. only 1), 2) and 4) are correct
4. none of the above.

Answer 1

Correct Answer - Option 4 : none of the above.

CONCEPT:

Magnetization (M): 

• It is defined as the magnetic moment per unit volume of the material. 
• Mathematically it is written as,

\(⇒ M=\frac{ m_{net}}{V}=\frac{m × 2l}{a\times 2l}=\frac{m}{a}\)

Where m_net = the dipole moment of the specimen, V = volume of the material, m = strength of each pole of the specimen, 2l = magnetic length of the specimen, and a  = uniform cross-section area of the specimen. 

• SI unit of magnetization Am^-1

Magnetic susceptibility (χ): ​

• It shows how magnetic material responds to the magnetic field.
• It is a dimensionless quantity.
• Mathematically it is written as,

\(\Rightarrow χ = \frac{M}{H}\)

Where H is the magnetic intensity

Relative permeability of the substance:

• The ratio of magnetic permeability of a material (μ ) to the magnetic permeability of the free space (μ0).

\(\Rightarrow μ_{r}=\frac{μ}{μ_{0}} =1+χ\)

EXPLAINATION:

• SI unit of permeability is Tesla meter/ Ampere (Tm A^-1)
• Platinum, aluminum, and chromium are three paramagnetic materials.
• Diamagnetic materials have a permeability of less than 1. In diamagnetic material magnetization, M and Magnetic intensity, H are in the opposite direction
• SI unit of magnetization is Am^-1. Hence option 4) is correct.

 

• Susceptibility (χ) is small and positive for paramagnets.
• susceptibility, (χ) is small and negative for diamagnets.