- In metal (eg copper), free electrons are the charge carriers. Electrical conduction in metal is due to the flow of free electrons through a lattice of positive ions The electric field setup by the battery establishes a force on the electrons, making them move in a net direction towards the positive terminal of the battery with a particular drift velocity.
For metals, resistance increases with temperature.
- As temperature increases, vibration of the lattice ions increases. Free electrons collide more frequently with the ions. Hence the electrons experience more obstructions and suffer a drop in drift velocity and hence experience greater resistance.
- Solids that have no mobile charge carriers. They do not conduct electricity.