Question

four particles with charges +5x10^-6C, +3x10^-6, +3x10^-6C, and +5x10^-6C are placed at the corners of a 2m x 2m square. (a)determine the electric potential at the center of the square, assuming zero potential at infinity. (answer:3.83x10^4V)(b) If one of the +3x10^-6C charges is replaced by a -4x10^-6C charge, what is the electric potential at the square's center? (answer: -6.36x10^3 V) Any help is appreciated.

Answer 1

To get the potential energy at any point P, add up the k*Qi/ri terms, where Qi is the charge of the ith particle and ri is it's distance away from point P. The sign of Q is important.

At the center, ri = sqrt2 meters for each corner particle

Do both problems the same way, but changing the value of one of the charges, qi. The other three charges stay the same.

Answer 2

there is a typo. the last charge is suppose to be -5c10^-6C

Can you check my work and see what I did wrong? Thank you!

Work:
K(5x10^-6C)/1 + K(3x10^-6)/1 + K(3x10^-6)/1+ K(-5x10^-6C)/1+K(5x10^-6C)/sqrt(2) + K(3x10^-6)/sqrt(2) + K(3x10^-6)/sqrt(2)+ K(-5x10^-6C)/sqrt(2)