Question

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

These materials are used to make magnets for electric generators, transformer core and electromagnet 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 transformers and $B$ for electric generators
• D. $B$ for electromagnets and transformers

Answer 1

Answer: (D)

Area of hysteresis loop is proportional to net energy absorbed per unit volume by the material, as it taken over a complete cycle of magnetisation.
For electromagnets and transformers energy loss should be low.
i.e., thin hysteresis curves.
Also $B=0$, when $H=0$ and $|H|$ should be small when $B=0$.