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4 charges, find potential 
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#1
Feb112, 03:33 PM

P: 204

1. The problem statement, all variables and given/known data
4 charges, distributed as follows 12*10[itex]^{6}[/itex] C @ (4,4) 12*10[itex]^{6}[/itex] C @ (4,4) 6*10[itex]^{6}[/itex] C @ (4,4) 3*10[itex]^{6}[/itex] C @ (4,4) Calculate the potential at the origin if the potential at infinity is zero. 2. Relevant equations V= U/q = W/q = ∫E*dl = k*q/r for multiple point charges, find V for each one, and sum them up 3. The attempt at a solution [itex]V1 = V2 = \frac{k*12*10^{6}}{(4*\sqrt{2}/2)} [/itex] [itex]V3 = \frac{k*6*10^{6}}{(4*\sqrt{2}/2)} [/itex] [itex]V4 = \frac{k*3*10^{6}}{(4*\sqrt{2}/2)} [/itex] [itex]V1+V2+V3+V4 = \frac{k*3*10^{6}}{4*\frac{\sqrt{2}}{2}}*(4+421) = 47676.7 [/itex] So, I factor out the k, the 3*10e6, and the 1/(r) from each Vi, then multiply it by 4+421 =5 this answer is not right. Any pointers? thanks!] 


#3
Feb112, 05:46 PM

P: 204

4^2 + 4^2 = 32 = 4 Sqrt(2) why, WHY did I divide by 2?! divided my solution by 2 (since it was sqrt(2)/2 in the divisor), and got the right answer! thanks! mods, please feel free to close topic 


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