(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Eight 3.0 μC charges are located at the corners of a unit cube centered about the origin with 1mm edges. How much work does it take to bring a 5.0 μC charge from infinity to the origin?

2. Relevant equations

U= k*q1*q2/r

3. The attempt at a solution

r= ((1*10^-3)^2+(1*10^-3)^2+(1*10^-3)^2))^(1/2)m

=1.73*10^-3m

U=(9*10^9)*(3*10^-6)*(5*10^-6)*8 / (1.73*10^-3)

=623.54 J

U at Infinite = 0

Work = 623.54 J

I have tried to explain why I have simply multiplied one result by 8 below.

The charge will have to have some path to get to the center of the cube and as a result there will be some time where it will be closer to some charges(a) than 1.73*10^-3m which would require more work to move the charge(b) closer than this. This extra work will be counter-acted as there will be negative work equal to this for the charge(b) to move away from the charge(a) once again.

Ok so this is the answer that I have obtained, unfortunately this is not one of the multiple choice options available. So I am not confident that I have completed the problem correctly, any feedback would be most welcomed.

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# Homework Help: Work to move charges from Infinity to origin

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