# Calculus with the electric field

1. Mar 25, 2007

### pakman2012

1. The problem statement, all variables and given/known data
1. Find the electric field at point P for a line segment with length L. Diagram attached.

2. Relevant equations

attached equations

3. The attempt at a solution

I have next to no clue on how to do this question. My first idea was to try and set up one of the lengths as r, and work from there, but I wasn't able to do anything conclusively. The most confusing part is not being able to do the calculus and relating the variables to fit the purposes of the problem. How exactly do you find the potential of something like this, in general?

Any help for this question will be greatly appreciated.

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• ###### Equations 1.bmp
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Last edited: Mar 25, 2007
2. Mar 26, 2007

### Galileo

First pick appropriate coordinate axes. The line along the x-axis and the left end at the origin for example.
Then consider the contribution to E resulting from a small line element dx (with charge density lambda say) and add up (integrate) all the contributions.

3. Mar 26, 2007

### giritrobbins

The trick is to use sine to relate the small section of conductor(dx) to the distance from your point.