Module 4.1 - Electricity: Charge and Current Flashcards
What is conventional current?
Current that flows from positive to negative
What is Electron flow?
Electrons flows from negative to positive
What is Current?
RATE of flow of CHARGE
What is a coulomb?
Unit of charge - J/s
What is the elementary charge (e)?
1.6 x 10^-19
What is the charge of an electron?
- e = - 1.6 x 10^-19
What is the charge of a proton?
+e = 1.6 x 10^-19
Fill the blanks:
Net charge on a particle or object is -1- and a -2- of e
1) quantised
2) multiple
What quantised charge mean?
Means that the charge only has discrete values
What two equations are used to calculate current?
I = Q ÷ t
I = ne
What is current in metals?
Movement of ELECTRONS
What is current in electrolytes?
Movement of IONS.
What are conduction electrons?
DELOCALISED electrons
What is Kirchoff’s first law?
The sum of currents ENTERING a junction in a circuit is EQUAL to the sum of currents LEAVING the junction - a form of conservation of charge.
What is drift velocity?
Average velocity of an electron in a material due to a voltage.
What is the equation to work out current using drift velocity?
I = nAev
What is n in I=nAev?
number density
What is number density?
The number of free electrons per unit volume
What is A in I = nAev?
Cross-sectional area
What is e in I = nAev?
Charge of an electron - 1.6 x 10^-19 C
What is v in I = nAev?
Mean drift velocity
What is the pattern in number density of conductors, semi-conductors and insulators?
Conductors : Large n ~ x10^29
Semi-conductors : Medium n ~ x10^19
Insulators : Small n ~ x10^9
Examples of conductors?
Metals, graphene, etc
Examples of semi-conductors?
Silicon, Germanium, etc
Examples of insulators?
Wood, Air and Plastic
