When we hear the term dipole, the first definition that comes to our mind is that a pair of opposing charges q and –q separated by a distance d is called a dipole. This definition is somewhere correct, but there is also another definition. The separation of charges within a molecule between two covalently bound atoms or atoms sharing an ionic bond is a dipole.

Types of Dipole

There are two types of dipoles

• Electric Dipole
• Magnetic Dipole

Let us understand them in detail.

What is an electric dipole?

An electric dipole is a pole where the positive and negative charges are separated by distance. The centre of an electric dipole is found at the midpoint between two magnetic poles. A pair of magnetic poles of opposite signs with equal magnitude is commonly considered as a dipole.

In simple terms, we can say that, 

• A system in which two equal and opposing point charges are positioned at a limited distance is known as an electric dipole. 
• The electric dipole moment is the product of any two charges multiplied by the distance
• The axis of the dipole is the line that connects the two charges. 
• Assume that the charges of an electric dipole are –q and +q, respectively, and that a modest distance of 2l separates them. Thus, p = q x 2l = 2ql gives the dipole moment of such a dipole.

What is a magnetic dipole?

• A magnetic dipole is made up of a magnetic north pole and south pole separated by a short distance.
• In the current loop, one senses the direction of the magnetic dipole moment by using his/her right hand and applying the right-hand grip rule.
• The magnitude of this magnetic dipole moment is computed by multiplying the current that runs through a conductor by the area (in SI units) of its cross-section.
• For example, bar magnets, magnetic needles, etc.

Magnetic Dipole Moment

Since the beginning of civilisation, magnetic properties have been known to people. At first, it was difficult for them to understand why magnets behave in such a way, but over time and with experience, mankind began to use their powers in some pretty interesting ways. Before we knew exactly how they worked or even where they came from, people had found plenty of practical uses for magnets, including using them as navigational tools like a compass and even keeping things together like on fridge doors! 

Today, modern scientists and scientists continue to discover how magnets work by observing their interactions and other actions performed with similar materials and objects. Understanding magnetic dipoles is essential to the mechanism of magnets. 

The magnetic dipole moment refers to a pair of equal and oppositely charged magnetic poles separated by a little distance. It describes the magnetic motions of these items.

Mathematical Representation of Magnetic Dipole Moment

B x m = ταυ

The torque exerted on our dipole by an outside magnetic field is referenced by the symbol “ταυ” in this equation, while the letter B refers to the strength of that external magnetic field. We represent the magnetic moment as ‘m’ in these equations, that is, it represents a sample that lacks any measurable intrinsic magnetic moment. 

Notably, this definition of m can only be applied to current loops as they are a sum of an actual measured current multiplied by the region of the loop in question.

Magnetic Dipole Concept

• A magnetic dipole is an example of what an electromagnet and magnet from your fridge comprise. 
• Both contain poles that are separated by a small distance. A current loop is a kind of dipole as it has two poles, the N-S pole and the S-N pole, with the same size but opposite directions for their magnetic fields stemming from the charges, which flow inside it. 
• Sometimes these three types of dipoles are related and can share similar qualities, for example, when the separation between the charge and its resulting field has the same ratio as in a current loop—but this is not always necessarily happening. 
• An example is how often the identity is mentioned between how electromagnets work and how magnets work inside refrigerators.

The magnetic dipole moment or strength of the magnet is described by the equation: m = IAN.

The magnetic dipole moment is represented by ‘m’. The units are Ampere metre square (Am²).

The magnetic dipole is a vector quantity in nature. We can find it by applying the right-hand thumb rule. The flow is perpendicular to the surface side, sealed by an anticlockwise path that simulates positive charge flow.

According to the SI standard, the dipole moment is measured in ampere-square metres. However, it is erg, a unit of energy per gauss, a unit of magnetic flux density, in the centimetre, the second system.

Conclusion

In this article, we have discussed the basics and types of dipoles. A pair of opposing charges q and –q separated by a distance d is called a dipole. An electric dipole is positive and negative charges that are separated by distance, and a magnetic dipole is made up of a magnetic north pole and a magnetic south pole that is separated by a short distance. Moreover, we talked about the magnetic dipole moment and learned about the magnet dipole concept.