08 charge and current Flashcards
What is current?
The rate of flow of electrical charge
What is 1 amp in terms of
coulombs?
1 coulomb passing a point in 1 second
What is charge?
a property of a material
What charge does an electron have?
-1.6x10(-19), -e
What charge does a proton have?
1.6x10(19), e
What is ‘e’ known as?
The elementary charge
What is the equation for current?
Change in charge/change in time
What does quantisation mean?
Charge is not a continues quantity
Which way do electrons flow in conventional current?
negative to positive
What is Kirchhoffs first law?
At a junction, the sum of the current into the junction equals the sum of the current out of the junction
How ammeters have high or low resistance?
low
What is the equation for current involving ‘number density of electrons’?
I=nAev
-n=number density of electrons
A= cross sectional area of wire
-e=elementary charge
V=drift velocity
What is a semi conductor?
Something with a number density between a conductor and insulator
