Potential difference between 2 points

AI Thread Summary
The discussion revolves around calculating the potential difference between two points, x and y, located at distances of 10 cm and 15 cm from a 60 microcoulomb charge in a vacuum. The user initially struggles with the formula for potential difference, specifically the term (1/ry - 1/rx), and expresses confusion over the calculation process. After attempting to determine the electric fields at each point and calculating the potential difference, the user realizes they made a simple mistake in their calculations. Ultimately, the user resolves their confusion and acknowledges the error. The thread highlights the importance of careful calculation in electrostatics problems.
ledwardz
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Homework Statement



2 points x and y, are along orthogonal directions from a 60uc charge. For x and y determine the potential difference between them. ( its in a vacuum also )
x= 10cm, y = 15cm

Homework Equations



okay, i know the equation is q/4*pi * EoEr *(1/ry - 1/rx)

what i don't understand is the end bit. the distance between them is not (1/ry - 1/rx)
can anyone explain to me how this works?

when i work out the electric fields at each point then multiply this by the distance to give me the potential difference (voltage) at each point too subtract one from the other i get the wrong answer. wtf is going on?

cheers for any help, Lee. :confused:
 
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ahh pooooo never mind I've done it stupid mistake ... my bad
 
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