2. Gravitational Electric
E
Electric vs. Gravitational
g Potential Potential
Energy Energy
Increases Increases
-
+
• Work is needed to • Work is needed to
push an object push a charge against
against gravity and a field and give it
give it Potential Electric Potential
Energy
Energy

3. Potential Difference
Potential Energy & Potential Difference
 Voltage (scalar or vector)
Divide both sides by qo What does voltage
and you get another actually measure?
physical quantity: – Measures how much
Electric Potential! energy a charge will
Otherwise known as gain/lose
voltage! – Measures how much
work that can be
done by a charge
If the Electric Field is
constant, it comes out of
the integral and you get
V = Ed

4. Allesandro Volta
Uniform Electric Fields
(Italian: 1745 – 1827)
Parallel Plates
Point
charge
Note the field lines
Uniform electric field

5. Battery gives the
electron 12 J of
Potential energy
e “loses” energy as it
travels through the
circuit.
Analogy
12 V
0V
Battery “gives” energy back
to electron to repeat cycle

7. • Sample Problem
Potential Energy & Potential Difference
A 9 V battery is connected to two parallel
plates that are separated by a distance of 0.30
cm.
a. What is the electric field?
b. How much energy would an electron have when placed
next to the positive plate?
+ + +
D = 0.04m
– – p+ –
a) V = E d b) Ue = q ∆V
9 = (E)(0.003m)
= (9 V)(1.6 x 10-19C)
Ue = 1.44 x 10-18 J
E = 3000 V/m

8. Key Ideas

9. times
charge
compliments of Mike Gearon
Flow Chart
times per unit = Potential
distance = Work
distance Gradient
per unit
charge

10. times
charge
compliments of Mike Gearon
Flow Chart
times per unit = Potential
distance = Work
distance Gradient
per unit
charge