Work done per unit charge by electric field on charge

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Homework Help Overview

The discussion revolves around the concept of work done per unit charge by an electric field on a charge, specifically focusing on the signs associated with work done in relation to electric potential and force direction.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the conditions under which work done by the electric field is considered positive or negative, questioning the relationship between force direction and displacement. There is an emphasis on understanding the implications of electric potential differences.

Discussion Status

Some participants have provided insights regarding the direction of electric field lines and the relationship between force and displacement. There is an ongoing exploration of the conditions that determine the sign of work done, with no explicit consensus reached yet.

Contextual Notes

Participants are discussing the implications of electric potential and the behavior of forces in electric fields, with some references to the definitions of work in physics. The original poster expresses uncertainty about determining signs, indicating a need for further clarification.

Cicicicici
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Homework Statement


Screen Shot 2018-05-25 at 2.37.17 pm.png


Homework Equations

The Attempt at a Solution


I know the units for V is J/C so #3 and #4 are wrong. But how do I determine the signs?
 

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Is the work done by the electric field positive or negative? What do you need to ascertain in order to answer this question? Hint: When is the work done by a force positive and when is it negative?
 
kuruman said:
Is the work done by the electric field positive or negative? What do you need to ascertain in order to answer this question? Hint: When is the work done by a force positive and when is it negative?
Work is positive when force is in same direction as displacement. So here the direction is X to Y and the force is also from X to Y because Vx>Vy?
 
Cicicicici said:
Work is positive when force is in same direction as displacement. So here the direction is X to Y and the force is also from X to Y because Vx>Vy?
Yes, electric field lines point from a region of high potential to a region of low potential. Since the charge is positive, the electric force on it is in the same direction as the electric field.
 
kuruman said:
Yes, electric field lines point from a region of high potential to a region of low potential. Since the charge is positive, the electric force on it is in the same direction as the electric field.
Thank you!
 

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