Electric Dipole

Introduction

An electric dipole is a pair of equal and opposite electric charges with non-coinciding centers. 

Electric dipole that is induced in an atom, in which the centre of the negative cloud of electrons has been displaced slightly away from the nucleus by an external electric field. 

The atom  loses its dipolarity in the situation when the external field is removed. 

A water molecule (H2O) that has two hydrogen atoms sticking out on one side and forms a 105° angle with the oxygen atom as vertex, is an example of persistent electric dipole.

Electric Dipole – Definition

An electric dipole is a pair of objects with equal and opposing charges separated by a significant distance. The first charge is supposed to be negative (-q), but the second charge is assumed to be positive (q). By default, electric dipoles in space are directed from negative charge ‘-q’ to positive charge ‘q.’ The point where ‘q’ and ‘-q’ meet is the dipole’s centre.

Example – A simple example of electric dipole is a water molecule (H2O) with two hydrogen atoms sticking out on one side and forming a 105° angle with the oxygen atom as vertex.

Significance  – It provides a thorough understanding of the molecule’s or species’ charge distribution. Even in the absence of an electric field, the study of electric dipoles helps in understanding the applications and behaviour of polar molecules with permanent electric dipole moments. This will also give you an overview of the various materials available, as well as their qualities and applications.

What is the Electric Dipole Moment?

Dipole Moment is a precise measurement of an electric dipole’s strength. According to mathematics and scientific studies, the dipole moment magnitude is the product of either charge and the separation distance ‘d’ between them. Keep in mind that the dipole moment is a vector measure with a charge direction of negative to positive.

Formula – 

The formula for electric dipole moment is 

p = q + d

where,

The magnitude of the charges is given by q, the magnitude of the distance between them is given by d, and the electric dipole moment is given by p.

Dipole Electric Field

Despite the fact that the two forces operating on the dipole end cancel each other out as free vectors, they behave as distinct points. Therefore, the dipole experiences a torque. Additionally, as a result of the torque, the dipole spins.

Consider the existence of an electric field on an electric dipole. The electric dipole will be subjected to some force, known as the torque. The torque is defined as the force exerted on dipoles in an external field and is computed as follows:

τ = p × E

In other form, we can write 

τ = p E sinθ

where,

τ is the dipole torque, E is the electric field and θ is the angle between the dipole and the electric field.

Therefore, in the presence of a homogeneous electric field, a dipole tends to align itself parallel to the concerned field. Other requirements must be followed, such as keeping the orientation at a non-zero angle, which is denoted by the letter ‘q.’ Furthermore, potential energy must be stored in the dipole at a preferred orientation that range from q = 0 to q > 0.

Physical Significance of Dipole

1. The study of electric dipoles helps in understanding the uses and behaviour of polar molecules with persistent electrical dipole moments even in the absence of an electric field.
2. Because the centres of positive and negative charge in most molecules coincide, their dipole moment is zero. However, when an electric field is applied, the centres of positive and negative charge move, resulting in a dipole moment. 
3. However, some molecules, such as H2O, have a permanent dipole moment even in the absence of an electric field. The study of the behaviour of these dipoles in various materials reveals interesting properties and vital applications.

Conclusion 

Electric dipole that is induced in an atom in which the centre of the negative cloud of electrons has been displaced slightly away from the nucleus by an external electric field. Even in the absence of an electric field, the study of electric dipoles helps in understanding the applications and behaviour of polar molecules with permanent electric dipole moments. The study of electric dipoles helps in understanding the uses and behaviour of polar molecules with persistent electrical dipole moments even in the absence of an electric field. However, when an electric field is applied, the centres of positive and negative charge move, resulting in a dipole moment However, some molecules, such as H2O, have a permanent dipole moment even in the absence of an electric field.