What is hysterisis? Define the terms 'coercivity' and 'retentivity' of a ferromagnetic material.

Explanation

Hysteresis: The phenomenon of lagging behind of magnetic induction (B) with respect to the magnetizing field (H) is called hysteresis.
Coercivity : It.s a phenomenon of completely demagnetizing the magnetic material by applying the magnetizing field in the opposite direction.
Retentivity: The property of the magnetic material to retain magnetismeven in the absence of the magnetizing field is known as retentivity.