Electricity Flashcards
What is a conductor?
Materials in which the outermost electrons leave their parent atoms and become free to move throughout the material.
What happens when an electric field is applied to a conductor?
The free electrons move opposite to the direction of field and have drift velocity, which is superimposed over their random motion.
Ordered drift is a flow of charge which is called ..
Electric current
What is the definition of electric current?
The total amount of charge crossing a particular cross-section of the wire per second.
What is the direction of current?
Direction is that of positive moving charges
What causes electrons to collide with positive ions in a wire?
electrostatic interactions
Do collisions affect motion and kinetic energy?
Collisions damp their average motion without decreasing kinetic energy.
In macroscopic relations what is the electric force balanced by?
Effective dissipation
How does a bigger electric field affect electrons and current of the wire?
The electrons flow faster and so the current increases with E.
How does the area of a conductor effect the current?
The larger the area of a current the bigger the current is.
How does the length of the wire effect the current?
The longer the wire the smaller the current
What is the inverse of conductivity?
Resistivity
What is the units for resistivity?
Ohm metres
What are the units for conductivity?
Ohms per metre
