Electric Fields
Visualizing the force that electric charges exert throughout space
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Electrical Field
Electric Potential Lesson - showmethephysics.com
Show Me The Physics
Lightning over the Icelandic volcano 2010
NASA
G) Electric Field - region in space where electric forces act on charges
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)
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
Negative Spherical Charges Drawn Positives
Electric Field Patterns Spherical Charges
Radial Fields
Field at the
What is the charge below - Negative, Positive or Neutral?
Physics
Animations
3 Dimensional View
Physics
Animations
e) Field between a positive and neutral charge
f) Field Lines between opposite charged parallel plates
** Field between plates is uniform
- (same strength all over)
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Check Your Understanding
5 quick questions — pick an answer to see if you’re right.
1. What is an electric field?
2. A 2.0 C charge feels a 6.0 N force in an electric field. What is the field strength?
3. By convention, the direction of an electric field is the direction of the force on
4. How do electric field lines around an isolated negative point charge point?
5. What is the electric field like between two oppositely charged parallel plates?
Probing the Field of a Charged Dome
A Van de Graaff generator’s dome is positively charged. A small positive test charge of 2.0 × 10−6 C placed at point P near the dome experiences a force of 0.050 N directed away from the dome.
What is the electric field strength at point P?
▶ Want a challenge? Open 6 more Regents-style questions (harder · mixed formats)
Challenge score: 0 / 6
C1. The dome is to the left of point P. An alpha particle (charge +2e = 3.2 × 10−19 C) is placed at P, where the field strength is 2.5 × 104 N/C. Choose the direction of the electric force on the alpha particle, and determine its magnitude.
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C2. An electron is placed at point P. What is the direction of the force on it?
C3. A student makes the following claim.
Place a check mark in either the Support or Refute box. Justify your response using a mathematical relationship.
C4. The 2.0 × 10−6 C test charge is replaced by a 5.0 × 10−6 C positive test charge at point P, where E = 2.5 × 104 N/C. Substitute numerical values into a mathematical representation that can be used to determine the magnitude of the force on the new test charge. Then calculate the force.
C5. In a drawing of field lines around the dome, where is the field strongest?
C6. Describe how students could use the small positive test charge and a force sensor to map the electric field around the dome. Identify the measurements they would make and how they would use them, and describe how the results would show where the field is strongest.