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184_notes:examples:week2_electric_potential_negative_point [2018/01/24 17:46] – [Solution] tallpaul | 184_notes:examples:week2_electric_potential_negative_point [2018/05/17 16:49] (current) – curdemma |
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===== Electric Potential from a Negatively Charged Balloon ===== | [[184_notes:pc_potential|Return to Electric Potential]] |
| ===== Example: Electric Potential from a Negatively Charged Balloon ===== |
Suppose we have a negatively charged balloon with total charge Q=−5.0⋅10−9 C. What is the electric potential (also called voltage) at a point P, which is a distance R=20 m from the center of the balloon? | Suppose we have a negatively charged balloon with total charge Q=−5.0⋅10−9 C. What is the electric potential (also called voltage) at a point P, which is a distance R=20 m from the center of the balloon? |
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We assume P lies outside of the balloon. This is obvious, as P is a distance R=20 m away from the center of the balloon. | We assume P lies outside of the balloon. This is obvious, as P is a distance R=20 m away from the center of the balloon. |
</WRAP> | </WRAP> |
{{ 184_notes:2_potential_positive_balloon.png?150 |Charged Balloon, and Point P}} | [{{ 184_notes:2_potential_positive_balloon.png?150 |Charged Balloon, and Point P}}] |
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===Goal=== | ===Goal=== |
<WRAP TIP> | <WRAP TIP> |
=== Assumption === | === Assumption === |
The electric potential infinitely far away from the balloon is 0 V. /*Read [184_notes:superposition#Superposition_of_Electric_Potential|here]] for why this is important.*/ | The electric potential infinitely far away from the balloon is 0 V. Read [[184_notes:superposition#Superposition_of_Electric_Potential|here]] for why this is important. |
</WRAP> | </WRAP> |
[184_notes:superposition#Superposition_of_Electric_Potential|here]] | |
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The electric potential at P is given by | The electric potential at P is given by |