topic 3 Flashcards
1
Q
current
A
rate of flow of charge
SI unit - C/s
1
Q
potential difference
A
work done per unit charge
SI unit - J/C
V = W/Q
2
Q
drift velocity
A
the velocity of the charge carriers
- I = nqvA (current depends on the mean drift velocity)
- directly proportional to current
3
Q
relationship between the quantities
A
1) doubling charge carriers doubles current
4
Q
A
5
Q
A
6
Q
A
7
Q
A
7
Q
A
8
Q
A
9
Q
A
10
Q
resistance
A
11
Q
three things that determine resistance
A
- length - longer the wire the more difficult it is to make a current flow
- area - The wider the wire the easier it is for current to flow
- resistivity - depends on the material the wire is made from
12
Q
resistivity
A
the resistance of a 1m length with a 1m2 cross-sectional area
measured in ohm metres
13
Q
Ohm’s law
A
provided the temperature is constant, the current through an ohmic conductor is directly proportional to the potential difference across it
