Electric Potential Lesson - showmethephysics.com

Show Me The Physics
YouTube Channel


Lightning over the Icelandic volcano 2010





G) Electric Field - region in space where electric forces act on charges


"Did you know that

sharks can 'see'

electric fields?"

School Blocks YouTube? Use file below.

Electroreception (right click, save as)


A bonnethead shark biting actively and vigorously at various electric dipoles while ignoring the live fish swimming around with it.

Dr. Stephen M. Kajiura,  Elasmobranch Research Lab,  Boca Raton, FL




1) Vector Quantity


2)  E = F/q  (on reference)


E = Electric Field Strength (N/C)
q = amount of charge
F = force on charge




AP Physics B

Giancoli p. 466) 31

E = F/q = ma/q


E = F/q = Kq/r2 


Corner charges cancel out 

E = F/q = Kq/r2 



3) The direction of an electric field is drawn to show how the field acts on positive charge (Decided by convention)


Positive Spherical Charges Repel Positives
Outward in all Directions


[ Flash ]

Negative Spherical Charges Drawn Positives
In Toward the Center of the Charge


[ Flash ] 


Electric Field Patterns

Spherical Charges


a) positive charge b) negative charge
ou+ in

Radial Fields


Field at the
center of a charge
= zero


What is the charge below - Negative, Positive or Neutral?

Physics Animations
- Pelletier Physics' Channel


c) 2 opposite charges


3 Dimensional View

Physics Animations
Pelletier Physics' Channel



d) 2 like charges






e) Field between a positive and neutral charge




Which charge is positive?


f) Field Lines between opposite charged parallel plates


** Field between plates is uniform


- (same strength all over)




Field Lines



Charges and Fields
Physics 2000

Charges and Fields Part II
Physics 2000


Identify the incorrect choices below.
Justify each choice


June 2013 

Name the charges.

June 2016

Field Intensity & d



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Use any material on this site (w/ attribution)