Question

The figure gives experimentally measured $B-H$ variation in a ferromagnetic material. Its retentivity, coercivity and saturation magnetization, respectively are:

• A. $1.5\text{T},50\text{A/m}$ and $1.0\text{T}$
• B. $150\text{A/m},1.0\text{A/m}$ and $1.5\text{T}$
• C. $2.5\text{T},50\text{A/m}$ and $2.0\text{T}$
• D. $1.0\text{T},50\text{A/m}$ and $1.5\text{T}$

Answer 1

The correct option is D $1.0\text{T},50\text{A/m}$ and $1.5\text{T}$


The retentivity measures the induced magetic field at which applied field is zero.

So, Retentivity $=\text{OA}=1.0\text{T}$

coercivity is the resistance of a ferromagnetic material to become demagnetized $=\text{OC}=50\text{A/m}$

$\therefore \text{coercivity}=50\text{A/m}$

At saturation magnetization; graph becomes horizontal

So, saturation magnetization $=M=1.5\text{T}$

Hence, option $\left(D\right)$ is the correct answer.