Question

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

 

These materials are used to make magnets for electric generators, transformer cores, and the electromagnetic core. Then it is proper to use:
A. (a) for electric generators and transformers
B. (a) for electromagnets and (b) for electric generators
C. (a) for transformer and (b) for electric generators
D. (b) for electromagnets and transformers

Answer 1

Hint: A plot between the magnetic force intensity (H) and the magnetization intensity (B). This is used to study the strength and the magnetic property of a ferromagnetic material. The curvature of this graph is the characteristic of the material. This curvature can change its size of curvature according to the material (narrow or wide).

Complete answer:
The hysteresis loop is formed when we apply a constantly increasing magnetic force. The magnetization (magnetic field) of the material increases with the force up to a certain value (positive saturation point). After this when the magnetizing force has decreased the decrease in magnetic force does not follow the same path there is a difference in the retarding path. The magnetic field decreases up to the (negative saturation point) of the material.

There are two main properties Retentivity and Coercivity

The higher the coercivity wide will be the loop in size. Wider the curvature better will be the material for the production of permanent magnets.
And narrow will be the loop better it will be better to use the material as an electromagnet.
So by comparing the graphs (a) and (b) given in the question. We can say that,
The material which has Plot (a) is good to make a permanent magnet
The material which has Plot (b) is good to make electromagnetic components.

So, the correct answer is “Option D”.

Note:
Ferromagnetic material shows strong magnetism in the external applied magnetic field. The direction of the developed magnetic field is always in the direction of the external force applied and the field lines are allowed to pass through the material. The magnetism in these materials is due to the alignment pattern of the atom. This material can be used to form electromagnets and permanent magnets for different uses.