Electric current - chapter 9 Flashcards
0
Q
Define coulomb
A
One coulomb is the amount of charge which flows past a point in a circuit in a time of 1s when the current is 1A
1
Q
What is the formula for charge?
A
Q=it
Charge = current x time
2
Q
What is elementary charge? (-e)
A
Elementary charge = 1.6 x 10^-19 C
3
Q
State kirchoffs first law
A
The sum of the currents entering any point in a circuit is equal to the sum of the currents leaving that same point
4
Q
Kirchoffs first law is an expression of what?
A
Kirchoffs first law is an expression of the ‘conservation of charge’
5
Q
What is the equation for current?
A
I = Anev
I = current A = cross sectional area n = number density e = elementary charge V = mean drift velocity
6
Q
What is an electric current?
A
An electric current is a flow of charge. In a metal this is due to the flow of electrons. In an electrolyte, the flow of positive and negative ions produce the current.
