Dipole in a Uniform External Field

Introduction

As we are familiar with the concept of an electric dipole, let us now look at the concept of torque on a dipole which is a simple topic and a scoring one. A dipole is a magnetised pole with an equal amount of positive and negative charges separated by distance (d). When a dipole is in a uniform electric field, it will experience some form of force and acquire a rotating effect. This rotating effect is known as ‘torque’. The term “torque” comes from latin, meaning “to twist”. Torque is a vector quantity, and its direction generally depends on the force applied to an object at any point. The Torque can be calculated by estimating the negative and positive charges’ overall rotation in an electric field. To understand the torque on a dipole in a uniform electric field. Let’s first revise the basic terms like “Torque”, “Dipole”, “electric field”, and dipole in a uniform external field study material.

Dipole

Dipoles are extremely prevalent. They are essentially two charges separated by some types of non-conducting medium (e.g., air, vacuum, etc.). An example of a dipole can be seen in the electromagnetic wave, where a dipole in a uniform electric field is polarised. A dipole in an electromagnetic system deals with the positive and negative charges separated by a distance. It is characterised by its dipole moment, a vector quantity. The forces associated with electric fields are mediated by the movement of charge. In the case of a simple dipole, there will be an attractive force between the positive charge and the negative charge, even if they are very distant from one another. The dipole moment is p = q x d q = the magnitude of charge & d = the separating distance.

Electric Field

The strength of an electric field is measured in Volt/metre [V/(m)]. An electric field has direction and magnitude, meaning it can have different magnitudes or directions, or both, in different regions of space. The electric field lines are the trajectories of the electric force; whenever an object with a charge moves through electromagnetic forces, it will follow these paths. The direction that the force is applied on determines which way the field line will be drawn (remember that as charges repel and opposites attract). The electric field is explained as E = F/q F = force exerts on the charge by an electric field q = the charge.

Torque on Electric Dipole

An electric dipole is defined as an electric charge pair that are both electric and of similar magnitude but charges opposite that have the distance ‘d’ between them. A dipole happens when there is a separation in charge, like when someone says “positively charged” or “negatively charged”. Dipoles are pretty much the same thing as charge separation. Unlike other vectors, the moment of an electric dipole has a specific direction, namely from negatively charged to positively charged. That is, p=qd. Here q is the charge of dipole and d is the distance between two charges. When there is a homogeneous electric field, the torque on an electric dipole is zero. Now assume a dipole that has the charges:  +q and –q that form a dipole because a distance of d separates them. In this case, the dipole should be positioned in the electric field that is uniform in nature and has sufficient strength, represented by E; here, the dipole’s axis generates an angle θ of the electric field. An electric dipole in a uniform external field experiences a torque given as τ = pE sin θ, where the symbol θ  denotes the angle between p and E. The moment of the dipole p tends to align in the direction of E as a result of the torque. The symbol gives the potential energy, which is of the dipole  U_e= −pE cos θ or in the vector notation that is U_e; = −p · E.

Conclusion

Here we learned about the dipole in a uniform electric field. The first-order component of the multipole expansion defines a dipole in uniform electric field theory. It consists of two opposed and equal charges, infinitesimally close together, even though the dipoles have different charges. When measuring at a distance far greater than the charge separation, the dipole, on the other hand, provides a decent approximation of the actual electric field. In areas such as physics, we frequently discover that the dimensions of a vast item may be ignored and represented as a pointlike entity that is a point particle.