Electric Charge & Its Nature-Dipole

Introduction

Electrostatics is highly reliant on the concept of an electric dipole. An electric dipole is a pair of charged objects separated by a small distance. Consider two charged objects separated by a small distance d and of equal magnitude Q, with the first charge remaining negative and the second charge remaining positive. This is called an electric dipole. Therefore we can say that an electric dipole is generated when equal and opposing charges are grouped and separated by a certain distance. In an electric dipole, the orientation is always from negative -q to positive charge +q.

Definition

A pair of equal and opposite point charges q and –q separated by a distance of 2a constitutes an electric dipole. A space direction is defined by the line connecting the two charges. The dipole’s direction is traditionally defined as –q to q. The dipole’s centre is defined as the intersection of –q and q locations.

The total charge of the electric dipole is zero. But It does not mean that the electric field is zero. Since the charges q and –q are separated by a certain distance, the electric forces produced by them do not exactly cancel out when put together. The fields related to q and –q almost cancel out over distances much greater than the spacing of the two charges producing a dipole (r >> 2a)

Physical significance of electric dipole moment

Not only is the theory of an electric dipole vital in physics, but it is also a valid and significant topic in chemistry.

Because most materials are formed up of atoms and molecules, we know that they are electrically neutral. The behaviour of the pair of charges is used to divide the molecules into two categories.

Polar molecule- A polar molecule is one in which the centre of mass of the positive charge does not match the centre of mass of the negative charge.

Non-polar molecules- Non-Polar molecules are those in which the positive charge’s centre of mass is the same as the negative charge’s centre of mass.

What is the electric dipole moment?

The product of the magnitudes of charge and dipole length determines the dipole’s moment. Electric dipole moment represents the strength of the electric dipole. It is a vector quantity and its charges move from negative to a positive direction. 

Formula: 

P = q × d 

Or

P= q x 2a 

Where P represents electric dipole moment, 

q represents the magnitude of the charge, 

d or 2a represent the total distance between the charges.

Difference between electric dipole and electric dipole moment

An Electric dipole is a system of two point charges which are equal in magnitude but have opposite natures and are separated by a small distance. The electric dipole moment, on the other hand, is the product of the charge magnitude and the distance between the centres of positive and negative charges. Although the charge magnitude of an electric dipole is q and the dipole moment is p, It is put in an electric field E that is uniform. Taking this into account, if its dipole moment is parallel to the field’s direction, the force on it and its potential energy is respectively.

Dipole placed in an Electric Field:

Even though the two forces operating on the dipole ends cancel each other as free vectors, they behave as independent points. Torque is generated on the dipole as a result of this. As a result of the torque, the dipole spins.

Consider an electric dipole that is in contact with an electric field. Torque will be applied to the electric dipole. The torque is the force exerted on dipoles in an external field, and it’s calculated like this:

τ = p × E

or

τ = p E sinθ

Where τ denotes the dipole torque,

E denotes the electric, &

θ is stated as the angle between dipole and electric field.

Conclusion

The electric dipole definition states that two equal and opposite charges separated by a little distance is an important aspect of electrostatic charge. The dipole moment is calculated by multiplying the magnitude of the charge by its distance, with the formula p = qd. The dipole moment is directed from a negative charge to a positive charge. The torque is the force exerted on a dipole and is computed as τ = PE, where τ denotes dipole torque, E denotes electric field, and a denotes the angle between the dipole and the electric field. The electric forces produced by the charges q and –q do not exactly cancel out when they are combined because they are separated by a certain distance.