1. The problem statement, all variables and given/known data what is the electric potential a distance x above the center of a ring of charge Q with a radius R surrounded by another ring of charge -Q with a radius 2R? 2. Relevant equations V= kQ/sqr root(a^2+x^2) 3. The attempt at a solution I know the above equation would be used for for one ring but would the second ring in this problem effect this equation?