Residual Magnetism Test: Hysteresis Quiz and Flashcards

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Questions and Answers

What is the term used to describe the lagging of magnetic flux density (B) behind the magnetic field intensity (H) when the current is decreased from its saturation value?

Hysteresis

What do we call the property where, after removing the magnetizing force (H), a magnetic material retains a small amount of magnetism?

Residual magnetism (Br)

What term is used to describe the negative value of magnetic field intensity (H) required to reduce residual magnetism to zero in a ferromagnetic material?

Coercive force (Hc)

Describe the behavior of magnetic flux density (B) when the value of magnetic field intensity (H) is decreased in the opposite direction after reaching saturation in a ferromagnetic material.

B decreases following a specific path until residual magnetism is reached in the opposite direction. Signup and view all the answers

What is the defining characteristic of ferromagnetic materials when the applied field is removed?

They retain a component of magnetization in the direction of the applied field. Signup and view all the answers

Why are iron, nickel, cobalt, gadolinium, and dysprosium known as ferromagnetic materials?

They exhibit a unique magnetic behavior called ferromagnetism. Signup and view all the answers

What are the two types of ferromagnetic materials mentioned in the text?

(a) Soft magnetic material and (b) hard magnetic material. Signup and view all the answers

What are the key properties of soft magnetic materials mentioned in the text?

High initial permeability, low coercivity, thin and narrow B-H curves, and low hysteresis energy losses. Signup and view all the answers

Define magnetic hysteresis.

Magnetic hysteresis is the phenomenon of lagging behind of induction flux density (B) behind the magnetizing force (H) in magnetic material. Signup and view all the answers

What is a hysteresis loop and what information can be obtained from it?

A hysteresis loop is a four quadrant B – H graph. From it, hysteresis loss, coercive force, and retentivity of magnetic material can be obtained. Signup and view all the answers

Explain the concept of magnetic saturation in the context of hysteresis.

Magnetic saturation occurs when the flux density (B) reaches its maximum value (Bm) for a given magnetizing force (H). Signup and view all the answers

How does the hysteresis loop change as the current in the circuit is varied?

As the current is increased, magnetizing force and flux density both increase, following the path from point o to a on the hysteresis loop. Signup and view all the answers

Study Notes

Ferromagnetic Materials

Hysteresis is the lagging of magnetic flux density (B) behind the magnetic field intensity (H) when the current is decreased from its saturation value.

Retentivity and Coercivity

Retentivity is the property where a magnetic material retains a small amount of magnetism after the magnetizing force (H) is removed.
Coercivity is the negative value of magnetic field intensity (H) required to reduce residual magnetism to zero in a ferromagnetic material.

Behavior of Magnetic Flux Density

When the value of magnetic field intensity (H) is decreased in the opposite direction after reaching saturation in a ferromagnetic material, the magnetic flux density (B) decreases, but not immediately, resulting in a lag behind the magnetic field intensity (H).

Characteristics of Ferromagnetic Materials

Ferromagnetic materials retain magnetism even when the applied field is removed.
Iron, nickel, cobalt, gadolinium, and dysprosium are known as ferromagnetic materials due to their ability to be magnetized and retain magnetism.

Types of Ferromagnetic Materials

There are two types of ferromagnetic materials: soft magnetic materials and hard magnetic materials.

Properties of Soft Magnetic Materials

Soft magnetic materials have high permeability, low coercivity, and low retentivity, making them suitable for applications where a strong magnetic field is required.

Hysteresis Loop and Magnetic Saturation

Magnetic hysteresis is the lagging of magnetic flux density (B) behind the magnetic field intensity (H) due to energy loss.
A hysteresis loop is a graph of magnetic flux density (B) versus magnetic field intensity (H), providing information on the energy loss and magnetic properties of a material.
Magnetic saturation is the maximum value of magnetic flux density (B) achievable in a material, reached when the material cannot be further magnetized.
The hysteresis loop changes as the current in the circuit is varied, resulting in a different energy loss and magnetic properties.

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Description

Test your knowledge on the concepts of hysteresis and residual magnetism in magnetic materials. Understand the relationship between current, magnetic flux saturation, and magnetization curves.