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CURRENT
Chapter 13.2
Electric potential energy
 The potential energy of a
charged object due to its
position in an electric field.
Potential Difference - Voltage
 When the ends of an electric
conductor are at different electric
potential energy, charge flows
from one end to the other.
 Charge flows when there is a
potential difference (voltage)
between the ends of a conductor.
Potential Difference - Voltage
 A battery or power source
creates a potential difference
between two ends of a conductor
by acting as an “electric pump”
creating charges on one end of
the conductor which flows
through the conductor and back
to the power source.
Electric Current
 Flow of charges through a
conductor.
Electric Resistance
 Caused by internal friction,
which slows the movement of
charges through a conductor.
 Thicker wires have less
resistance than thinner wires.
 Resistance decreases in cooler
temperatures.
Symbols & Units
Name
Symbol
Unit
Resistance
R
ohms or Ω
Voltage
V
Volts (V)
Current
I
Amperes (A)
Ohm’s Law
V = IR
I = V/R
R = V/I
Answers to Practice Problems
1)
2)
3)
4)
5)
6)
30 Ω
240 Ω
6V
0.43 A
108 V
2.5 A