8 - Charge and current Flashcards
What is charge?
Charge is physical property that measures how charged something is.
What does the symbol “e” represent?
Elementary charge - the charge of one proton
1.6x10-19
How can electric current be defined?
The rate of flow of charge.
How do you calculate the number of electrons transferred?
Q/e
What is the direction of conventional current?
Positive to negative
What is an electrolyte?
A liquid that can carry an electric current, either due to being molten ionic compounds or in a solution.
What causes the flow of electrons in a metal wire?
Delocalised electrons being attracted to the positive end of the wire and repelled from the negative end of the wire.
What is Kirchhoff’s first law?
For any point in an electrical circuit, the sum of currents into that point is equal to the sum of currents out of that point.
What does the conservation of charge mean?
Electric charge can neither be created or destroyed. The total amount of electric charge in the universe is constant.
What is number density?
The number of free electrons per cubic metre of material.
Compare the number densities of conductors, semiconductors and insulators.
Conductors = high number density Semiconductors = medium number density Insulators = low number density
What is mean drift velocity (v)?
The average speed that charge carriers move at.
What equation links current and drift velocity?
I = Anev
Do batteries have charge?
No
What do batteries do to electrons?
Move them around the circuit.
