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This text is meant to accompany class discussions. It is not everything there is to know about uniform circular motion. It is meant as a  prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations (click here.)
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Electric Fields Due to Point Charges

 

Introduction video below.

This video can be seen on YouTube at https://youtu.be/ll0gu1nAPow

 

Every body that has a net charge radiates an electric field, called an e-field. These e-field are vectors. They have magnitude and direction. The magnitude is calculated from the equation below.
Formula
Variables defines

The direction of the field is simple to determine with a single, stationary, point charge in space. It is the direction a positive charge would travel. Another words the field points away from positive charges and towards negative charges.

If multiple charges are present then the DIRECTION of the e-field is determined by:

  • Finding the direction of the e-field due each point, (one at a time.)
  • Breaking up the e-field vectors into horizontal and vertical components.
  • Adding up these components to find the net e-field's horizontal and vertical component -like you have done previously with free body diagrams.
  • Make a solution triangle to calculate the e-field's magnitude and direction.

 

This video shows you how to find the net e-field due to 2 charges by finding each e-field's magnitude and direction followed by adding these up vectorially.

This video can be found on YouTube at http://youtu.be/IyS3LKrtCG0

Example
  • Question
  • Video Solution

Calculate the net electric field at the point in space shown below.

setup's image

Video of this solution on YouTube is here: http://goo.gl/3APT3N

 
Quiz
Well not yet. But soon. ...at some point.
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by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)