Question

The magnetic properties of the different materials A, B and C are shown in the following table:

Material	Permeability	Susceptibility	Temperature dependence of susceptibility
A	Low positive	Small but negative	Independent of temperature
B	High	Very high 1	Susceptibility decreases with temperature
C	Greater than 1	Small but positive	Decreases with temperature

Which of the above three materials should be used for making an electromagnet and why?

Answer 1

The material to be used for making an electromagnet should have high permerability and low retentivity. Moreover, less energy should be utilised for magnetisation of the material.

Thus, material B should be used for making the core of an electromagnet.