Question

The figure illustrate how $B$ (the flux density inside a sample of unmagnetized ferromagnetic material) varies with $H$ (the magnetic flux density in which the sample is placed). If we want to use this sample for making core of a transformer, then,

• A. $\text{OQ}$ should be large and $\text{OR}$ should be small.
• B. $\text{OQ}$ and $\text{OR}$ both should be large.
• C. $\text{OQ}$ and $\text{OR}$ both should be small.
• D. $\text{OQ}$ should be small and $\text{OR}$ should be large.

Answer 1

The correct option is C $\text{OQ}$ and $\text{OR}$ both should be small.

In the $B-H$ graph shown, $\text{OQ}$ represents the retentivity and $\text{OR}$ represents coercivity.

For making core of a transformer, both of them should be as small as possible.
eg- soft iron

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