Which of the following portions represents retentivity in the BH curve shown below?

Point 2 represents the retentivity in the BH curve.

Hysteresis curve

The hysteresis loop shows the relationship between the magnetic flux density and the magnetizing field strength.

Looking at the graph, if B is measured for various values of H and if the results are plotted in graphic forms, then the graph will show a hysteresis loop.

• The magnetic flux density (B)  is increased when the magnetic field strength (H) is increased from 0 (zero).
• With an increase in the magnetic field, there is an increase in the value of magnetism, and it finally reaches point A, which is called the saturation point where B is constant.
• With a decrease in the value of the magnetic field, there is a decrease in the value of the magnetism. But if B and H are equal to zero, when a substance or material retains some amount of magnetism, it is called retentivity or residual magnetism.
• When there is a decrease in the magnetic field towards the negative side, magnetism also decreases. At point C, the substance is completely demagnetized.
• The force required to remove the retentivity of the material is known as Coercive force (C).
• In the opposite direction, the cycle is continued where the saturation point is D, the retentivity point is E, and the coercive force is F.
• Due to the forward and opposite direction process, the cycle is complete, and this cycle is called the hysteresis loop.