# 6. Discrete and Continuous Distributions of Charge

« Previous | Next »

## Learning Objectives

• To be able to describe the physical meaning of the electric potential.
• To be able to describe the meaning of the work done in moving an electric charge in an electric field, and to be able to relate that concept to the electric potential.
• To be able to calculate the electric potential due to a set of point charges.
• To be able to calculate the electric potential of a uniform electric field.

## Preparation

### Course Notes

Read through the course notes before watching the video. The course note files may also contain links to associated animations or interactive simulations.

Electric Potential (PDF)

## Lecture Video

### Video Excerpts

Flash and JavaScript are required for this feature.

## Learning Activities

### Guided Activities

Read through the class slides. They explain all of the concepts from the module.

Slides (PDF)

### Self-Assessment

Do the Concept Questions first to make sure you understand the main concepts from this module. Then, when you are ready, try the Challenge Problems.

### Concept Questions

Concept Questions (PDF)

Solutions (PDF)

### Challenge Problems

Challenge Problems (PDF)

Solutions (PDF)

## Problem Solving Help

Watch the Problem Solving Help videos for insights on how to approach and solve problems related to the concepts in this module.

### Problem 1: Electron Moving in an Electric Field

An electron is shot at t = 0 with a speed of v = 2.5x106 meters/second into a homogeneous E field of 1x10Newtons/Coulomb in the direction that causes it to slow down.

1. Sketch E and v in their relative configuration.
2. How far will the electron travel?
3. How long a time will it take for the electron to return to its original position?
4. Suppose now that the E field ends after only 10 millimeters. What fraction of the kinetic energy was lost in passing through the field?

Flash and JavaScript are required for this feature.

» iTunes U (MP4 - 9MB)
» Internet Archive (MP4 - 9MB)

### Problem 2: The Potential of Two Opposite Charges

A negative charge -q sits on the positive y-axis at a distance a from the origin, and a positive charge +q sits on the negative y-axis at the same distance a from the origin. What is the electric potential everywhere on the y-axis?

Flash and JavaScript are required for this feature.