Question

Magnetic materials used for making permanent magnets $\left(P\right)$ and magnets in a transformer $\left(T\right)$ have different properties of the following, which property best matches for the type of magnet required?

• A. $T$ : Large retentivity, small coercivity
• B. $P$ : Small retentivity, large coercivity
• C. $T$ : Large retentivity, large coercivity
• D. $P$ : Large retentivity, large coercivity

Answer 1

The correct option is D $P$ : Large retentivity, large coercivity

Permanent magnets $\left(P\right)$ are made of materials with large retentivity, to retain higher magnetization and large coercively to avoid demagnetization in practical usage.

But, the Transformer cores $\left(T\right)$ are made of materials with low retentivity and low coercivity as the core will be undergoing cycle of magnetization and demagnetization.

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