Fig above represents the hysteris is loop, which is graph B Vs H.

1) At P, B become constant & called as saturation value & the state of specimen is called magnetic saturation.

2) When the current is reversed as well reduced, the curves follows the path PQ & the value of B corresponding to point Q is called remanent induction.

3) On further reduction of H on negative side the specimen gets completely demagnetized i.e. B=O corresponding to point R. The value of H=OR is called coercive field & this effect is called coercive.

4) Further increase in negative H makes the specimen saturation & with constant max. B of opposite polarity.

5) Again the specimen gets completely gets demagnetized at μ when direction of H is reversed as well as increased.

6) Finally, the curve takes up the path UP & thus the curve traces the closed path PQRSTUP & the process repeat.

Thus summarize the lagging of flux density B w.r.t the magnetizing force H is called ‘Hysteresis’ & the closed loop graph is known as ‘Hysteresis’ loop.