Question

5.(i) write two characteristics of a material used for making permanent magnets. (ii) why is core of an electromagnet made of ferromagnetic materials?

Answer 1

(i) For making permanent magnets the material must have high retentivity and high coercivity

(iii) Ferromagnetic materials have high magnetic permeability compared to air. Ferromagnetic core increases the self-inductance of the loop proportional to their relative permeability. Due to this reason, the core of an electromagnet is made of ferromagnetic material.