Short Answer:

An electric dipole is a pair of equal and opposite electric charges placed close to each other at a small distance. One charge is positive and the other is negative, and together they create a special electric field pattern around them. The strength and direction of a dipole are measured using a quantity called dipole moment.

The dipole moment is the product of the charge and the distance between the charges, and it points from the negative charge to the positive charge. Electric dipoles are found in molecules and are important in understanding electric fields, forces, and polarization in materials.

Detailed Explanation:

Electric dipole

An electric dipole is a basic and important concept in electrostatics. It consists of two equal charges with opposite signs, usually denoted as +q and –q, that are separated by a small fixed distance 2a. The line joining the two charges is known as the dipole axis. Even though the total charge of a dipole is zero, it still affects the electric field around it due to the separation of the charges.

Dipoles are very common in nature, especially in chemistry and physics. For example, many molecules such as water (H₂O) behave like dipoles because they have separated centers of positive and negative charges. Dipoles help in understanding electric fields, forces on charges, and how materials respond to external electric fields (polarization).

Dipole moment

The effect of an electric dipole is described by a quantity called electric dipole moment. It gives both the strength and direction of the dipole.

Dipole Moment (p):

p⃗=q×2a\vec{p} = q \times 2ap​=q×2a

Where:

• q = magnitude of each charge
• 2a = distance between the charges
• p = dipole moment (vector quantity), direction is from negative to positive charge
• Unit = coulomb-meter (C·m)

Dipole moment tells how strong the dipole is. A larger value means stronger influence on the surrounding electric field.

Electric field due to a dipole

An electric dipole produces a special electric field pattern that is different from a single point charge. The electric field around a dipole depends on the position where you are measuring it:

• On the axial line (along the line connecting the charges):
  The electric field is strong and points away from the positive charge if you’re far from the dipole.
• On the equatorial line (perpendicular bisector of the dipole):
  The field is weaker and points opposite to the direction of the dipole moment.

At large distances, the electric field (E) due to a dipole decreases faster than for a single charge. It follows an inverse cube law:

E∝1r3E \propto \frac{1}{r^3}E∝r31​

Applications of electric dipoles

1. Molecular chemistry: Many molecules act as dipoles, and this affects their bonding and properties.
2. Polarization of dielectrics: When a material is placed in an electric field, small dipoles are formed inside it, which helps in storing electric energy.
3. Sensors and instruments: Dipoles are used in electric field sensors and other measuring devices.
4. Communication systems: Antennas often behave like electric dipoles when they transmit or receive signals.

Conclusion:

An electric dipole consists of two opposite charges placed close together. It is described by its dipole moment, which indicates its strength and direction. Although the total charge is zero, a dipole still creates an electric field and plays an important role in many electrical, chemical, and physical processes. Understanding dipoles is essential in studying electric fields and the behavior of materials in external electric forces.