Current is flow of electrons???

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1. What is Current? Flow or Vibration?

  • In metals, electrical conduction happens because of free electrons (loosely bound outer electrons of atoms).



  • When an electric field is applied (e.g., by connecting a battery or generator), these free electrons drift very slowly through the lattice. This is called drift velocity — typically a fraction of a mm/s.

  • However, the signal (electromagnetic wave) travels through the conductor at nearly the speed of light, which makes it appear as if electricity moves instantly.

🔑 So, current is not just vibration.
Electrons do drift (flow), but very slowly. At the same time, they also oscillate/vibrate due to alternating electric fields in AC circuits. Both concepts coexist:

  • DC circuits → electrons flow slowly in one direction.

  • AC circuits → electrons mainly vibrate back and forth about their mean positions, with almost no net displacement.

2. Why Metals Don’t “Run Out” of Electrons

  • You raised a good point: If electrons are consumed, won’t the metal lose conductivity?

  • Electrons are not consumed. They are just rearranged by the electric field.

  • In a closed circuit, electrons that leave one end of a wire re-enter at the other end (continuity of current).

  • The energy that powers the load (like a bulb or motor) comes from the electric field created by the source (battery, generator), not from "using up" electrons.

Think of it like water in a pipe:

  • The water molecules (electrons) don’t disappear.

  • The pump (battery/generator) pushes them, transferring energy.

3. Role of Vibrations in Conductivity

  • Inside a metal, free electrons are already in random thermal motion (~10^6 m/s).

  • When a voltage is applied, they gain a small net drift velocity superimposed on this random motion.

  • In AC circuits, the direction of drift reverses every half-cycle, which is why electrons mainly "vibrate" instead of moving far.

This is why in power plants (alternators):

  • No new electrons are created.

  • The rotating magnetic field induces an electric field in conductors, causing free electrons to oscillate (vibrate) back and forth.

  • The result: energy transfer via electromagnetic fields, not consumption of electrons.

4. Factors Affecting Conductivity of Metals

You summarized well. Two major factors:

  1. Number of free electrons per atom (Copper > Aluminum > Iron).

  2. Mobility of electrons (inversely related to resistivity, depends on scattering, temperature, and lattice structure).

That’s why:

  • Copper is a better conductor but costlier.

  • Aluminum is used in power lines (cheaper, lighter, though higher resistivity).

✅ Final Clarification

  • Current = flow of charge (drift of electrons).

  • In DC, electrons drift one way slowly.

  • In AC, electrons mainly vibrate about their mean position, but the energy is transferred via the electromagnetic wave, not by transporting electrons across the circuit.

  • Electrons are never consumed — only their energy states change under the influence of an electric field.


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