# Electric Currents in Conductors, Mechanism of Current Flow in a Conductor (For CBSE, ICSE, IAS, NET, NRA 2022)

Get top class preparation for competitive exams right from your home: get questions, notes, tests, video lectures and more- for all subjects of your exam.

# Electric Currents in Conductors

• Electrical Conductors are most important part of our lives.
• The entire power grid is made up of electrical conductors and insulators.
• Recently we՚ve added another term, ‘semiconductors’ to this.

• Imagine a body, invariably made up of atoms.
• The atoms are made of electrons, protons, and neutrons.
• If being loosely connected, electrons are able to move freely inside the body, which is called electrical current.
• Under normal condition, the electrons are moving randomly inside the body and hence the net electric current is zero since they all cancel each other out.
• The application of an electric field around the body is also another way to cause movement in electrons but the catch is that the electric field does not influence everything.
• This is where the distinction between electrical conductors and insulators comes in electricity.
• The electric field can cause the electrons to move around.
• Through this influence on electrons, we can give a net direction to the motion of the electrons.
• This is how we generate an electric current.

## Mechanism of Current Flow in a Conductor

• Flow of current in metals is due to preferential flow of free electrons. In the absence of any externally applied emf (by means of a battery) , the free electrons move randomly through the metal from one point to another giving zero net current.
• When connected to a battery, the free electrons get accelerated due to the electric field (set up by the battery) and they gain velocity and energy.
• Though, the passage is not smooth and the electrons collide with the lattice ion in which the ultimate gainer (of energy) is the ion.
• If we know the temperature of a body is related with the energy of vibrations of these ions, these collisions result in increase in temperature of the metal.
• The loss of energy of electrons in collision and their acceleration by the electric field, finally, results in drifting of electrons in a particular direction. (Although the actual motion of electrons is erratic, the overall effect is of drifting of electrons) .
• The motion of the conducting electrons in an electric field is thus a combination of the motion due to random collisions.
• When we consider all the free electrons, their random motion average to zero and make no contribution to the drift speed.
• So, the drift speed is only due to the effect of the electric field on the electrons.

## Conductors

• Bodies in which the application of an electric field results in the generation of an electric current due to the movement of the electrons is called an Electrical Conductor.
• In such bodies, the electrons are free to move around inside the body and their random motion can be influenced by an electric field.
• Most electrical conductors are metals mainly because metals possess electrons in the outermost orbit where they are most loosely held and can move around easily.
• The wires supplying electricity to your houses are supplying fresh energetic electrons to your house for you to use.

## Insulators

• Some bodies do not possess free moving electrons like metals.
• Materials with fixed electrons such as plastics and rubber do not respond to the electric field at all.
• The electrons in these materials are not free to move around and generate an electric current.
• Such bodies are called Electrical Insulators.
• The plastic coating around the wire is an insulating material which prevents you from getting shocked by the electricity in the wire within.

Developed by: