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A2L Item 135

Meta-Information
Description: 
Select the situation for which the movement of a negative charge through an electric field results in the greatest increase of potential energy.
Goal: 
Link electric fields, work and potential energy
Level: 
Undergraduate
Keywords: 
Electromagnetism
Keywords: 
Potential Energy
Keywords: 
Work
Source: 
283-455 Change in Potential Energy when moving a charge

In each of the situations below a negative charge is moved along a path from point A to point B in the presence of an electric field, as shown. For which situation is the increase in potential energy the greatest?

Commentary

Answer

(2) In case 1 the charge moves to a lower potential energy. In case 3 the charge returns to a point having the same distance to the plane of charge as it originally had, meaning no net work. In case 4 the charge moves along an equipotential and no work is done. Students should be asked to identify the charge configuration that could account for each of these field situations. They can also be asked for which case is the electrostatic potential change the greatest.