1. The problem statement, all variables and given/known data You want to create an electric field = < 0, 3x10^4,0 > N/C at location < 0, 0, 0>. Where would you place a proton to produce this field at the origin? 2. Relevant equations 1/4?? * q/r^2 = 3x10^4 N/C (if you can't see the 1/4th part of the equation it's 1/(4(pi)(epsilon-not)) == 9.0x10^9 or just k) 3. The attempt at a solution I moved everything over so that I can solve for r^2 and got this as my equation: r = sqrt((9.0x10^9)(1.6x10^-19)/(3x10^4)) I ended up getting 2.19x10^-7 however its' saying it's not correct. I have it set up as a vector: <0, 2.19x10^-7, 0> Does it need to be negative for a proton in relation to the electric field?