Understanding Electron Behavior in Conductors
When an electric field is applied to a conductor, the initial velocity of electrons is effectively zero. This phenomenon can be explained through the following concepts:
1. Nature of Conductors
- Conductors, like metals, have free electrons that can move throughout the material.
- Initially, these electrons are in random motion due to thermal energy, but their net drift velocity is zero.
2. Application of Electric Field
- When an electric field is applied, it creates a force on the free electrons.
- However, at the moment the electric field is first introduced, the electrons have not yet had time to respond to this force.
3. Collisions with Lattice Ions
- Electrons frequently collide with fixed lattice ions in the conductor.
- These collisions disrupt the motion, preventing a net movement in a specific direction despite the presence of an electric field.
4. Drift Velocity Development
- After applying the electric field, electrons begin to accelerate in the direction of the field.
- Over time, as they experience fewer collisions in the direction of the electric field, they develop a net drift velocity.
5. Steady-State Condition
- Eventually, a steady state is reached where the average drift velocity of electrons becomes constant.
- This drift velocity is directly proportional to the strength of the electric field, resulting in a continuous electric current.
In summary, while electrons in a conductor start with zero net velocity due to random thermal motion and frequent collisions, the application of an electric field eventually leads to a drift velocity as they respond to the force exerted by the field.