1. The problem statement, all variables and given/known data What is the magnitude of the E field at the origin due to a single charge (either the + or the -) located 5 cm above the horizontal axis? 2. Relevant equations KQ/D^2 3. The attempt at a solution in an earlier question it asked What is the direction and magnitude of the E field at the origin due to the single negative charge (ignore all others) on the horizontal axis?" SO i used columbs law "KQ/d^2, (8.99x10^9x30x10^-9)/.05^2 and i got 1.1x10^5 which was the correct answer, but this questions answer is supposed to be 5.4X10^4. I was wondering why this is the case as all the numbers are the same from an earlier question, exepct now its vertical.