Hysteresis loops for two magnetic materials A and B are given below:

These materials are used to make magnets for electric generators, transformer core and electromagnet core. Then it is proper to use:

1. Material A:

Properties: This material has a large area within its hysteresis loop. It features high retentivity (residual magnetism when $$H=0$$) and high coercivity (resistance to being demagnetized).

Suitability: Because it is difficult to demagnetize and retains a strong magnetic field, it is ideal for making permanent magnets, such as those used in electric generators.

2. Material B:

Properties: This material has a narrow, thin loop. This indicates low coercivity and low hysteresis loss (the energy dissipated as heat during each cycle of magnetization).

Suitability: In devices like transformers and electromagnets, the magnetic field is constantly switching (alternating current). To prevent the device from overheating and to ensure high efficiency, you need a material that can be easily magnetized and demagnetized with minimal energy loss.

Applications: Specifically used for transformer cores and electromagnet cores.