Question

The magnetizing field required to be applied in opposite direction to reduce residual magnetism to zero is called
(A) retentivity
(B) coercivity
(C) hysteresis
(D) flux

Answer 1

Hint: Use the hysteresis to explain the behavior of the substance under the varying magnetic strength and give information about the given statement so that the correct answer can be determined.

Complete step by step solution:
Different types of substances show different magnetic behavior under various conditions. The magnetization and demagnetization of the substance is performed to obtain the desired result for the various applications in the study of physics. So the characteristic of the substance under the magnetization and demagnetization condition is shown in the hysteresis curve for a better understanding.

This curve relates the magnetization intensity to the magnetizing field. If the curve increases, it means that the strength of the substance's magnetizing property is increasing. But if this magnetized substance is demagnetized, then the curve will not follow the same reverse-path during demagnetizing. It will follow the different path toward the negative axis, and the point on which the curve meets the negative axis gives information about the coercivity measuring. Thus, the phenomenon of demagnetization of the substance with the help of the application of the magnetic field in the opposite direction is known as coercively.

Therefore, option (B) is correct; the magnetizing field required to be applied in the opposite direction to reduce residual magnetism to zero is called coercivity.

Note: Apply the magnetic field in the reverse direction to demagnetize the substance. The soft iron's coercivity is less than the steel's coercivity, so the soft iron loses its magnetism property more rapidly than steel does.