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Experiment 3: Electric Field Mapping Introduction Every electrically charged object produces an electric field around it at all points in space affecting all other surrounding charged objects

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Experiment 3: Electric Field Mapping

Introduction

Every electrically charged object produces an electric field around it at all points in space affecting all other surrounding charged objects. The properties of this field are entirely determined by this “source” charge. In the case of a positive point charge, as shown in the image below, the electric field E

 points radially outward in all directions. The magnitude (or “strength”) of this field is greatest where the density of electric field lines is highest; in the image, the lines are most dense near the point charge, where E

 is greatest, and the lines are least dense radially away from the point charge, where E

 is least.

 

 

Note that is the source was negatively charged Q, the direction of the electric field would be, toward the point charge. Therefore, electric field lines radiate away from the positive charges and terminate at negative charges. Because the electric field has both a magnitude and a direction, it is known as vector field.

 

 

This “rule” of opposite charges attracting and like charges repelling each other, however, does not have an intuitive explanation based on these definitions.

 

In this lab exercise we simulate the electric field pattern for 1. two like charges of equal magnitude; 2. two opposite charges of equal magnitude; 3. two like charges of unequal magnitude; 4. two opposite charges of unequal magnitude. These four configurations are shown in Figure below

    

 

                      

 

 

 

 

                       

 

 

 

Procedure

Computer Simulation Online: Charges and Fields

https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html

 

Part A:  Mapping opposite charges (configurations 2. and 4.)

1. Place opposite charges of +1nC and -1nC five large boxes away and observe the electric field pattern

 

 

 

2. Take the screenshot of the field pattern (use the drop-down menu at the lower right corner) and attach it to your lab report
3. Increase positive charge by ten times (up to +10nC) by dropping additional charges at the same spot and observe changes in the electric field pattern. Take a screenshot and attach it to your lab report.

 

Part B:  Mapping like charges (configurations 1. and 3.)

Follow the same procedure as in part A but replace the negative charge with the positive one. Attach the screenshots to your lab report.

 

 

 

 

 

 

Questions:

1. What is the main difference between the field pattern of like charges and the field pattern of opposite charges of equal magnitude? Describe the difference

 

 

 

 

 

 

 

 

2. How does the field pattern changes when the magnitude of one of the charges increases a)in the case of  like charges and b) in the case of the  opposite charges. Describe the change.