Concept of Magnetic Field

Introduction:

The magnetic field of an object tends to create a magnetic force on other objects along with the other magnetic fields. This force is called magnetism. 

Whenever a magnetic field is applied to an electric charge that is moving, such as a moving proton or the electrical current in a wire, the force on the charge is called a Lorentz force.

Body : 

Magnetism is the force with which a magnetic force can be created around objects with magnetic fields. The magnetic field can be defined as the place around a magnet or current-carrying conductor around which magnetic effects are often experienced. Explaining further, it’s a vector quantity, and the SI unit of the magnetic field is Tesla (T) or Wbm‒2. It’s so astonishing to know that the magnetic and electric fields are both similar and different, and they are also interrelated.

The magnetic field is a dipole field which means that every magnet must have two poles.

On the flip side, a positive (+) or negative (−) electrical charge can stand alone.

• Monopole – It is a pole or an electric charge which is single
• Dipole – a couple of opposite poles
• The moment of the magnets is the measure of the strength of the dipole

Attraction

When two or more-than-two magnets or magnetic objects are pretty close to each other, there is a force that attracts the poles together.

Repulsion

Whenever two magnetic objects have poles that are facing or opposite to each other, the magnetic force pushes them apart.

Magnetic and electric fields

The fact that the magnetic and electric fields are both similar and different. They are also interrelated.

Electric charges and magnetism similar

In electrical charges, the positive (+) and negative (-) charges attract each other. Similarly, in the magnets, the north (N) and south (S) poles attract each other.

What happens in electricity is that like charges repel, whereas in magnetism, like poles repel.

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Forms of magnetism

Diamagnetism

It is the property of an object where it causes a weak magnetic field in opposition to an externally applied magnetic field. It is a type of magnetism that’s only shown by a substance within the presence of an externally applied magnetic flux.

Paramagnetism

It is a type of magnetism that takes place only in the presence of an externally applied magnetic field. Paramagnetic materials are strongly interested in magnetic fields, hence have a relative magnetic permeability greater than one (or, equivalently, a positive magnetic susceptibility).

Molecular magnet

 A single-molecule magnet or SMM is an object composed of molecules, each of which behaves like a private superparamagnetic. This is different from a molecule-based magnet, in which a group of molecules behaves collectively as a magnet.

Antiferromagnetism

The moments of the magnet’s atoms or molecules are usually associated with the spins of electrons, aligned during a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions.

Ferrimagnetism

The ferrimagnetic material is one in which the moment of a magnet of the atoms on different sublattices is strongly opposed, as in antiferromagnetism; however, in ferrimagnetic materials, the opposing moments are not equal, and a spontaneous magnetization remains.

Metamagnetism

It is the increase in the magnetization of a material with a small change in an externally applied magnetic field. The metamagnetic behavior tends to possess different physical causes for different types of metamagnets.

Magnetic fields and forces

Similar situations that form magnetic fields (charge occupation a current or in an atom, and intrinsic magnetic dipoles) are also where a magnetic flux has an effect, creating a force. Following is the formula for moving charge of magnetic field 

F = qvB sinθ

When a charged particle moves through a magnetic flux B, it feels a force F given by the cross product: 

F = q (vB)

Where q  is given as the electric charge of the particle, v is given as the velocity vector of the particle, and B is the magnetic field. Because this is often a vector product, the force is perpendicular to the particle’s motion and, therefore, the magnetic flux.

Properties:

• Magnetic lines of force always begin from the North Pole and end at the South Pole
• The lines are continuous through the body of a magnet
• Magnetic lines of force can undergo iron more easily than air
• Two magnetic lines of force cannot intersect one another
• They tend to contract longitudinally
• They tend to expand laterally

Magnetic force on current-carrying conductor

Whenever a current-carrying conductor experiences magnetic forces in a magnetic field, Fleming’s Left-Hand Rule predicts the direction of the magnetic forces,

F = ILBsinθ

Here, F is the magnetic force, I is the current, L is the length of a straight conductor in a uniform magnetic field B, and θ is the angle between I and B.

Conclusion: 

• The magnetic field can be defined as the space around a magnet or current-carrying conductor around which magnetic effects can be experienced

• Whenever a magnetic field is applied to an electric charge which is moving, such as a moving proton or the electrical current in a wire, the force on the charge is called a Lorentz force

• The different types of magnetism are diamagnetism, paramagnetism, ferromagnetism, antiferromagnetism,ferrimagnetism, superparamagnetism, and metamagnetism