Electric Dipole

The atoms of elements contain protons and electrons. The tons are the fundamental sub-particles of atoms that are positively charged. The electrons are the fundamental sub-particles to atoms that revolve around the protons and carry the negative charge. 

Opposites attract the rule of nature. Since both these charges interact with each other, that leads to concepts like electromagnetic fields and dipole moments.

Now, what exactly is the dipole moment?

The dipole is formed when two opposite charged particles, which are similar in magnitude but opposite in charge, are separated by a certain distance.

Dipole 

In the simplest terms, the dipole is the separation of two charges: the positive charge and the negative charge. 

There are two types of dipoles. The formula of the dipole moment is different for a different type of dipole. The types of dipoles are given below.

• The Electric Dipole:

The two poles here are the positive charge and negative charge. The positive charge attracts a negative charge and repels a positive charge. A negative charge attracts a positive charge and repels the positive charge.

• The Magnetic Dipole:

 In the magnetic dipole, the separation is between the north pole of the magnet and the south pole of the magnet. They are just like the electric charges; the similar poles repel each other and the opposite poles attract each other. 

Among these, let us study in-depth about the electric dipole.

The Electric Dipole

The electric dipole is the separation of two opposite charges, that is, the positive charge and the negative charge in an electromagnetic system.

The distance between these charges is considered small. The magnitude of these two charges has to be exactly similar as two charges with different magnitudes cannot be considered.

The electric charge in an electric dipole is equated to 0. However, that does not mean that the electric field of the dipole is also zero. The dipole is like a balance between opposite charges. The positive charge nullifies the total effect of the negative charge and vice versa. In order to maintain this balance, the magnitude of the two opposite charges needs to be the same.

The Formula of Electric Dipole

Since the strike dipole is a vector quantity, it will have a magnitude as well as a direction. Let us take a look at the electric dipole moment formula.

To calculate dipole moments, even the massive objects should be considered as points. 

We can do the calculation in the following way.

Let us suppose that there are two points charges. The magnitude of both of the charges should be similar. Hence, the magnitude of both point charges will be equal to q. Now, both the charges are supposed to have opposite charges. Hence one point charge will be +q and the other point charge will be -q. 

Now we need to separate them by a distance. This should not be too much. Let us consider this distance to bed; the dipole moment is the product of the magnitude of the charges and the distance by which the charges are separated. So, the formula for electric dipole will become:

P = q × d

Here P is the measure of electric dipole moment.

The electric dipole moment determines the intensity of the electric dipole to produce an electric current. 

Electric dipole unit and dimensions

The dimensions of a unit depend upon the formula and fundamental units that make up those derived units.

The dipole moment is always directed from the negative charges to the positive charges.

The following are the units of the dipole moment. 

The S.I. unit used to measure the electric dipole moment is Coulomb – Metre, which is 

C-m.

The C.G.S unit used to measure the electric dipole moment is Coulomb – Metre that is stat coulomb – centimetres, also known as Debye.

With respect to the above units, let us derive the dimensional formula for the electric dipole moment. 

The mass will be raised to 0 power, the power of length dimension will be 1 and the time and current will also be raised to 1. Hence the dimensional formula will become:

M0L1T1I1

The dipole in an external electric field

If a dipole is placed in the external electric field, then it will experience a force called the torque.

The formula to calculate this force or the torque is given below.

Torque = P × E 

= P × E × Sin θ 

Here the P represents the dipole moment. While the external field in which we have placed the dipole is represented by E.

Such is the electric dipole moment and formula for the same.

Conclusion

The dipole is the separation of opposite charges at a small distance. The dipole is of two types: the electric dipole and the magnetic dipole. These dipoles are created due to the positively charged and negatively charged sub-particles present in an atom of an element.

The electric dipole moment is a vector quantity. The moment is always from the negatively charged particles to the positively charged particles. The dipole helps in the calculation of bond angles in chemical molecules and chatting the percentage of the ionic character. The S.I. unit of the Coulomb – metre.