Core of electromagnets are made of ferromagnetic material which has

Core of electromagnets are made of ferromagnetic material which has Correct Answer high permeability and low retentively

Concept:

Ferromagnetic materials:

• In some materials, the permanent atomic magnetic moments have a strong tendency to align themselves even without any external field.
• These materials are called ferromagnetic materials.
• In every unmagnetized ferromagnetic material, the atoms form domains inside the material.
• Different domains, however, have different directions of magnetic moment and hence the materials remain unmagnetized.
• On applying an external magnetic field, these domains rotate and align in the direction of the magnetic field.

Explanation:

• For an electromagnetic core, the permeability must be highly permeable to produce a maximum magnetic field to get maximum output
• Also, for quick response as soon as the current through the electromagnet is stopped core should easily get demagnetized this property of losing its magnetization is known as retentivity
• Hence the core of electromagnet must have low retentivity so that it gets demagnetized easily.