Question

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

Solution
Verified by Toppr

Hysteresis: The phenomenon in which the magnetic induction (B) lags behind with respect to the magnetizing field H is called hysteresis.
It occurs when an external magnetic field is applied to a ferromagnet such as iron and the atomic dipoles align themselves with it. Even when the field is removed, part of the alignment will be retained: the material has become magnetized. Once magnetized, the magnet will stay magnetized indefinitely.
Retentivity: The property of the magnetic material to retain magnetism even in the absence of the magnetizing field is known as retentivity or remanence.

Coercivity: The magnetizing field (H) needed to demagnetize the magnetic material completely is known as its coercivity.

874557_946844_ans_5150fb6e75784ddf9e2620cf3fd38cbd.JPG

Was this answer helpful?
8
Similar Questions
Q1

The figure gives experimentally measured Bāˆ’H variation in a ferromagnetic material. Its retentivity, coercivity and saturation magnetization, respectively are:



View Solution
Q2

The mass of a specimen of a ferromagnetic material is 0.5 kg and its density is 8000 kg/m3. What is the energy equivalent area of hysteresis loop of alternating magnetizing field of frequency 100 Hz, if the hysteresis loss per second is 240Ɨ10āˆ’3 J/s?

View Solution
Q3

The figure gives experimentally measured B vs H variation in a ferromagnetic material. The retentivity, co-ercivity and saturation magnetization, respectively, of the material are:
View Solution
Q4

When a ferromagnetic material goes through a hysteresis loop, its thermal energy is increased. Where does this energy come from?

View Solution
Q5

Electromagnets are made of soft iron because soft iron has
(a) high retentivity and high coercive force
(b) high retentivity and low coercive force
(c) low retentivity and high coercive force
(d) low retentivity and low coercive force

View Solution
Solve
Guides