• # Electric dipole moment

Why the electric dipole moment is directed from negative to postive charge and not from positive to negative charge?
• because electrons(negatively charged particles) move faster than proton(postively charged particles

• Hi Kamath,
In any material medium positive charges lie inside the nucleus and electrons revolve around the nucleus in free orbits. When external changes like electric field or magnetic fields are applied these electrons get excited to their higher level orbits and are out of their stationary orbits. As electrons consist of negative charge they are attracted by the positive charge and hence move towards them. This is the phenomenon of the dipole moment of electrons directed from negative to positive charges.

Regards,
K.Prithvi.

Regards,
Prithvi Kocherla.
"Success is not the end of life, but it is the turning of a new page".

• There are two types of charges +ve and -ve. Normally atom is neutral if it losses one electron is called as an ion it has +ve charge and electron has negative charge.

I think you know electric field lines or electric flux, it is vector quantity. The directrion of electric flux start from positive charge and end at negative charge. Hence the direction of positive charge is direction of electric field.

If a potential difference applied to a conductor i.e. at one end of conducting wire positively charged and another charged with negative, then field is from positive to outwards but, due to attraction of positive charge electrons moving againest the direction of field but positively charged ions are not moving any where.

The electric dipole moment is given by the distance between negatively charged electron and positively charged ion if they are seperated by an electric field. The electric dipole moment is directly proportional to distance between positve and negative chage (fig. in attachment).

i.e. P = q x d.

Where P - electric dipolemoment, q- is charge and d- distance between two charges.

But the only electron is mobile, the distance between two charges hence dipole moment is found by moving electron only hence the dipole moment is directed from electron to positive charge.

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• In current electricity topic, we come to know that free electrons are responsible for flow of electric current in the conductor. In metallic conductor, per each atom there would be a free electron. Collectively, free electrons for all atoms in the condutor are solely responsible for electric current in the circuit. When we put the electric field by connecting to ends of the conductor. As a result, free electrons move with an average velocity in a direction opposite to the field.
As per conventional mode, even we consider the direction of electric current is opposite to the direction of flow of electrons such that the direction of positive charge motion is taken to be the direction of electric current.
Electric dipolemoment is a measure of separation of positive and negative charges in a system of charges. But electric dipolemoment depends upon the direction of electric field by which it seperate the positive and negative charges. So we can take the direction of electric dipolemoment as the direction of electric field which is connected to the ends of the conductor.

• Hi Kamath,
In any material medium positive charges lie inside the nucleus and electrons revolve around the nucleus in free orbits. When external changes like electric field or magnetic fields are applied these electrons get excited to their higher level orbits and are out of their stationary orbits. As electrons consist of negative charge they are attracted by the positive charge and hence move towards them. This is the phenomenon of the dipole moment of electrons directed from negative to positive charges.

Regards,

• We know there are two charges +ve charge and -ve charge and we know that electrons are responsible for flow of current current flows from lower potential to higher potential,as electrons flows but the current flows opposite to the direction of electrons i.e current flows from -ve to +ve and that is the reason electric dipole moment is directed from negative to positive charge.