Electric Energy and Potential

Student Learning Objectives
Lessons / Lecture Notes
Important Equations
Example Problems
Applets and Animations

Student Learning Objectives

• To introduce electric potential energy and use it in conservation of energy problems.
• To define the electric potential.
• To find and use the electric potential of point charges and charged spheres.
• To establish the relationship between electric field and electric potential.
• To introduce and use equipotential surfaces.
• To learn the properties of a conductor in electrostatic equilibrium.
• To introduce batteries as a practical source of potential difference.

Lessons / Lecture Notes

The Physics Classroom (conceptual)

PY106 Notes from Boston University (algebra-based):

Introductory physics notes from University of Winnipeg (algebra-based):

HyperPhysics (calculus-based)

PHY2049 notes from Florida Atlantic University (calculus-based):

PHY2044 notes from Florida Atlantic University (calculus-based)

General Physics II notes from ETSU (calculus-based)

Important Equations

Example Problems

Problem 1
(a) In a television picture tube, electrons strike the screen after being accelerated from rest through a potential difference of 25000 V. Ignoring relativistic effects, find the electron speed just before the electron strikes the screen. (Solutions)

(b) Two electrons are moving directly toward one another. When they are very far apart, their initial speeds are 1.35 × 106 m/s. What is the distance of closest approach? (Solutions)

Problem 2
Three point charges are fixed in place as shown in the figure below. (a) Determine the electric potential at point P (assuming V = 0 at infinity). (b) How much electric potential energy would an electron placed a point P have? (Solutions)

Applets and Animations
 Charges and Fields Move point charges around on the playing field and then view the electric field, voltages, equipotential lines, and more. It's colorful, it's dynamic, it's free. Electric Field and Potential Model The Electric Field and Potential Model shows the electric field and potential for cylindrical and spherical symmetry. In both symmetries, there are co-centric charged surfaces where the outer surface is grounded. The model reports the force on a test charge (yellow) between the co-centric surfaces as well as the voltage. Parallel Plate Capacitor The Parallel Plate Capacitor model displays a parallel-plate capacitor which consists of two identical metal plates, placed parallel to one another. The capacitor can be charged by connecting one plate to the positive terminal of a battery and the other plate to the negative terminal.