
An electric dipole is an important concept in electrostatics. It is described as a pair of equal and opposite charges separated by a small distance. If the total charge on a dipole is zero, it can produce electric fields. Also, it helps to understand the behaviour of the electric field around charged systems, molecules and atoms.
The electric dipole moment is used to study the strength and direction of a dipole. The moment is from negative charge to positive charge. The use of electric dipole is in Physics and chemistry. It is used to study polar molecules, dielectric materials, and electromagnetic waves propagation. Knowledge of electric dipole will help to build a strong foundation for various physical phenomena in modern Physics and chemistry.
Also Read:
NCERT Class 12 notes | |
NCERT Class 12 Maths notes |
- What is Electric Dipole?
- Electric Dipole Moment
- Electric Potential due to a Dipole (V)
- Electric Dipole Practice Problems
- Complete Class 12 Study Material
What is Electric Dipole?
When two equally opposite charges are separated by a small distance, this system of charges is known as an Electric dipole.
A big question is, since both charges are opposite in nature, why don't they fall into each other?
In reality, the electric dipole doesn't exist as a free system of charges; there is always an external force, such as inter ot intramolecular forces, or external mechanical forces, which balances both charges.
There are three important constituents of an electric dipole.
- A positive charge is denoted by
- Negative charge is denoted by
- Distance between charges
Key properties of Electric Dipole
It inhibits some special properties. It is important to know the properties asked in the board exams. Read the properties below;
- The electric field at the midpoint joining the line is always zero.
- An electric dipole produces an electric field even the its net charge as a system is zero.
- The dipole moment represents the directionality and possible force exerted on the dipole when placed in a field.
- The electric field due to a dipole decreases with distance.
Electric Dipole Moment
An electric dipole is a very important concept in class 11 physics. You can check the class 11 dipole moment and related properties below.
Dipole Moment
The dipole moment of an electric dipole provides a measure of polarity, which means it shows strength and direction. Since it is a vector quantity, it indicates the direction of polarity. It is calculated as the product of the magnitude of the charge and the distance between these two charges (separation distance).
So, mathematically,
where:
= dipole moment
= magnitude of each charge
= distance between charges
Direction of Dipole Moment
We fixed the direction of the dipole moment according to a convention agreed upon (by the scientific world). The scientific community has fixed the direction which negative charge to positive charge for convenience.
If you draw a line from the negative charge towards the positive charge, colinear to the axis of the dipole, this will represent the direction of the dipole moment.
Electric Potential due to a Dipole (V)
Let's assume there is an electric dipole with two charges: +q and -q. These charges are separated by a distance d. if we divide this distance d in a way that the O is mid midpoint and the distance of the charge from mid midpoint is r.
Then the formula for electric potential;
The electric potential due to a dipole:
In case, θ = 90°
Electric Potential (V) = 0
When, θ = 0°
Electric Dipole Practice Problems
You can solve these practice questions below for better understanding.
1. A dipole with two charges of equal and opposite charges with magnitude separated by a distance in a uniform field . The angle between E and the axis of the dipole . Find the torque.
2. What will be the electric field at a point 0.1 m away from a dipole that has a dipole moment on its axial line?
Complete Class 12 Study Material
Physics Electric Charge and Field Exam
Student Forum
Other Class 12th Physics Chapters
- Physics Alternating Current
- Physics Ray Optics and Optical Instruments
- Physics Electromagnetic Induction
- Physics Dual Nature of Radiation and Matter
- Physics Semiconductor Devices
- Physics Wave Optics
- Physics Current Electricity
- Physics Nuclei
- Physics Electrostatic Potential and Capacitance
- Physics Atoms
- Physics Moving Charges and Magnetism
- NCERT Class 12 Notes
- NCERT Class 12 Physics
- Physics Electric Charge and Field
- Physics Electromagnetic Waves
- Physics Magnetism and Matter