الفيزياء العامة الجزء الثاني#موقع الفيزياء.كوم

Lectures in General Physics
5.3 Electric Potential and Electric Field
Simple Case (Uniform electric field):
The potential difference between two points A and B in a Uniform electric
field E can be found as follow,
Assume that a positive test charge q o is moved by an external agent from A
to B in uniform electric field as shown in figure 5.4.
The test charge q o is affected by electric
force of q o E in the downward direction. To
B
move the charge from A to B an external
force F of the same magnitude to the
electric force but in the opposite direction.
The work W done by the external agent is:
F
W AB = Fd = q o Ed (5.2)
Dd
Ddl
Oq o
Oq o
E
The potential difference V B -V A is
V
WAB
− VA
= Ed (5.3)
q
B =
o
A
Figure 5.4
E
This equation shows the relation between the potential difference and the
electric field for a special case (uniform electric field). Note that E has a
new unit (V/m). hence,
Volt
Meter
=
Newton
Coulomb
Dr. Hazem Falah Sakeek