Chapter 8: Charge and Current Flashcards
what is electric current
flow of charged particles
what is current measured in
Amps/amperes
what is the electrical current in a metal due to
movement of delocalised electrons
what is the electrical current in an electrolyte due to
movement of ions
what is conventional current
flow of particles from +ve to -ve
what is electron flow
flow of electrons in circuit from -ve to +ve
what is the charge equation
Q = I x t Charge = Current x time
what is charge measured in
Coulomb
what is the elementary charge and its value
charge of one electron/proton
1.6 x 10^-19C
what is the quantisation of charge
all charges are multiples of e- because charges on objects are a result of gaining or losing electrons
what is Kirchhoff’s first law
the total current before a junction is equal to the total current after the same junction
what is the drift velocity equation
I = n x A x v x e Current = number density (number of free charge carriers per unit volume) x cross sectional area x mean drift velocity x elementary charge
what is the first step to find mean drift velocity
use the area and length to find the volume
what is the second step to find mean drift velocity
in a short time an amount of charge passes a point so do n x e (number density x elementary charge)
what is the third step to find mean drift velocity
since n is actually density Q = n x A x L x e
