ONLINE ACTIVITY
PART 1: Electric Fields
Name: __________________________
Go to www.physicsclassroom.com
and click on “Physics Tutorial” on the left. Choose Static Electricity and click on Lesson
4a “Action-at-a-Distance”.
1.
Read the sections “The Electric Field Concept” and “A Stinky Analogy”. What is an electric field and how can it be compared to a stinky diaper?
Google: Regents Physics Static Electricity. Once at the site, click on the link for “Electric Field Mapping”.
2.
Where does an electric field exist?
3.
What does the positive test charge do when placed in between the large positive and negative charges?
4.
Draw the electric field map for the following scenarios: a.
b. c.
+
+ + + + + + + + +
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+ d. See if you can do this one!
+
- - - - - - - - -
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Go back to the Regents Physics site and click on “Electric Field Strength (Field Intensity)”.
5.
Where is the electric field the strongest? Where is it the weakest? How do you know?
6.
What equation can be used to find the strength of an electric field (E)?
Where the units of E are:
7.
What “hybrid” equation is found by combining the above equation and Coulomb’s Law?
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PART 2: Electrical Field with Phet
Purpose: In this lab you will investigate how a charge creates a field around itself, how test charges behave when place in that field, and how the field varies for different point charge distributions. Then you will apply these concepts to an
Electric Field Hockey Game.
1.
Google: PhET. Once you are at the site, click on “Play with Sims”. On the left, click “Physics”, then “Electricity,
Magnets & Circuits” and find the simulation called “Charges and Fields”. Click “Download Now!”
2.
Place a 1nC positive charge and E-Field sensor in the test area. Click Show E-Field to observe the field lines and observe the sensor’s arrow as you drag it around in the field. a.
What do you observe? b.
Replace the positive charge with a negative charge (remove charges by dragging them back into their box). How does this change the electric field? c.
By convention, field arrow point ________________ with a positive charge and __________ with a negative charge. As the sensor gets closer to a point charge, the field strength created by that field is
____________.
3.
Set up a positive charge and a negative charge in the test area, along with an E-Field sensor (Show E-Field still on). a.
Describe the electric field around this two-charge configuration (i.e. what would the electric field line configuration look like? Include reference to direction and strength.) b.
What happens if you move the charges closer together? c.
What happens if you move the charges farther apart? d.
Put another negative charge directly on top of the one that is already in the test area. How does this change the electric field in the test area? e.
The basic law of electrostatics states that opposite charges will _______________ . How might this be supported by electric field in the test area?
4.
Set up 2 positive charges in the test area, along with an E-Field sensor (Show E-Field still on). a.
Describe the electric field around this two-charge configuration (i.e. what would the electric field line configuration look like? Include reference to direction and strength.) You might want to include a drawing. b.
What happens if you move the charges closer together? c.
What happens if you move the charges farther apart?

d.
Put another positive charge directly on top of the one that is already in the test area. How does this change the electric field in the test area? e.
How would this electric field change if you replaced all of the positive charges with negative charges? f.
The basic law of electrostatics states that like charges will _______________ . How might this be supported by electric field in the test area?
5.
Set up a configuration in the tests area with at least 3 charges of any sign combination, along with an E-Field sensor (Show E-Field still on) a.
Describe the configuration that you set up with a drawing. b.
Describe the electric field of this configuration (i.e. what would the electric field line configuration look like? Include references to direction and strength). Include a. drawing
PART 3: Electric Field Hockey
Google: PhET. Once you are at the site, click on “Play with Sims”. On the left, click “Physics”, then “Electricity, Magnets
& Circuits” and find the simulation called “Electric Field Hockey”. Click “Run Now!” and begin in the Practice mode.
1.
What is the charge of the puck?
2.
Bring out some charges and click on the “Field” box. Put a check mark in the “Trace” box then click “Start”.
What do the arrows represent?
Put a check mark in the “Field” box to confirm or reject your answer from above.
3.
How can the arrows help you in this game?

PART 4: Conclusion Questions and Calculations
1.
Closer to the point charge, the electric field created is stronger/weaker.
2.
Placed exactly between two oppositely charged point charges, a test charge (the sensor) will show zero/
minimum /maximum force (N) or field strength (N/C), compared to having the test sensor placed on a point charge.
3.
Placed exactly on a point charge, the sensor will show zero/ minimum/ maximum field strength.
4.
The point charges used in this simulation are +/- 1.0x 10 -9 C (nanoCoulomb). If two such positive charges are placed a distance of 2.0 m away from each other, the electric force between them would be (use the Coulomb’s law formula).
SHOW WORK.
Fe= ___________________
5.
Using the electric force from above, what is the magnitude of the electric field produced 2.0m away from one of the charges, using a test charge of 1 x 10 -10 C? Use the E = F/q formula.
SHOW WORK.
E= ___________________
6.
A test charge of 4.5 C in a field of strength of 2.2 N/c would feel what force? Use the E = F/q
SHOW WORK.
F= ___________________
7.
A balloon is electrostatically charged with +3.4 uC (microCoulomb 1.0 x 10 -6 ) of charge. A second balloon .23m away is charged with -5.1 uC of charge. The force of attraction/repulsion between the two charges will be:
SHOW WORK.
Fe= ___________________