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13 Cards in this Set
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Electrical Current 
The rate of flow of charged particles 

Conventional Current

A model used to describe the net movement of charge in a circuit. Conventional current travels from the positive terminal to the negative terminal. 

Conservation of charge 
Charge is conserved in all interactions. It cannot be created or destroyed.


Kirchoff's First Law 
The sum of all the currents entering any point in an electrical circuit is always equal to the sum of currents leaving the circuit at that point, as charge is conserved.


Coulomb 
1 coulomb is equal to the electric charge carried by 1 ampere (amp) of current in 1 second 

Ampere 
The current flowing in two parallel wires in a vacuum 1 metre apart such that there is an attractive force of 2.0x10^7 N per metre length of wire between them. 

Number Density

The number of free (or delocalised) electrons per metre cubed of a material.


Conductor 
A material with a high number density of conduction electrons and therefore a very high resistance. 

Insulator 
A material with a low number density of conduction electrons and therefore a very high resistance


Semiconductor

A material with a lower number density of conduction electrons than a conductor and therefore a higher resistance


Mean Drift 
The average velocity of electrons as they move through a wire. 

Resistance 
R = V / I Where: R = resistance (ohms) V= pd (V) I = current (A) 

Resistivity 
The resistance of a wire with a length of 1m and a cross sectional area is 