# Lesson Plan: Electric Fields of Point Charges

This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to relate electric forces to electric fields and describe the electric field lines produced by groups of charges.

#### Objectives

Students will be able to

- relate the electric force, , on an object that has a charge of due to the presence of an electric field, , using the equation ,
- determine the electric field, , at a distance of from a point charge , applying the equation, , where is the Coulomb constant,
- recognize that an electric field can be represented by field lines,
- recognize that an electric field line must start at a positively charged object and terminate at a negatively charged object,
- recognize that an isolated positive charge has electric field lines starting from it that extend to infinity in all directions,
- recognize that an isolated negative charge has electric field lines terminating at it that extend from infinity in all directions,
- recognize that the directions of electric field lines in a region represent the directions of electric field vectors in the region,
- recognize that the density of electric field lines in a region represents the magnitude of the electric field in the region,
- recognize that the electric field lines of an isolated point charge are radial lines,
- rank and/or estimate the electric charge values of point charges by inspecting the diagrams of the field lines of the resultant electric fields around the point charges.

#### Prerequisites

Students should already be familiar with

- Coulomb’s law.

#### Exclusions

Students will not cover

- descriptions of the resultant field line patterns due to symmetrical distributions of electric charge.