 Physics Help Forum Finding the Electric Field as a Result of Two Point Charges

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum Oct 2nd 2014, 08:23 PM #1 Junior Member   Join Date: Oct 2014 Posts: 1 Finding the Electric Field as a Result of Two Point Charges The problem: There is a −3 µC point charge at (0,0,4) and a +3 µC point charge at (0,0,-4). What is the magnitude and direction of the electric field at point (0,0,8)? What is the magnitude and direction of the electric field at point (4,4,0)? The attempt at a solution: It should be as simple as just adding the electric field caused by each point charge. (0,0,8) (0,0,8) - (0,0,4) = (0,0,4) (0,0,8) - (0,0,-4) = (0,0,12) k_e −3 μC (0,0,4) / 4^3 + k_e 3 μC (0,0,12) / 12^3 -1685.625 + 187.29166 = -1498.33334 However, the answer I should be getting (apparently) is 609 (4,4,0): (4,4,0) - (0,0,4) = (4,4,-4) (4,4,0) - (0,0,-4) = (4,4,4) ke −3 µC (4,4,-4) / (4^2 + 4^2 + 4^2)^(3/2) + ke 3 µC (4,4,4) / (4^2 + 4^2 + 4^2)^(3/2) ke −3 µC (4,4,-4) / (48)^(3/2) + ke 3 µC (4,4,4) / (48)^(3/2) (-324.4, -324.4, 324.4) + (324.4,324.4,324.4) = (0,0, 648.8) However, the answer I should be getting is 487 Am I doing something wrong? Last edited by blazerqb11; Oct 4th 2014 at 12:50 AM.  Tags charges, electric, field, finding, point, result Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post romakarol Electricity and Magnetism 0 Feb 24th 2016 06:03 PM puggleboy Electricity and Magnetism 5 Feb 1st 2016 07:41 AM pranimaboity2050 Electricity and Magnetism 0 Apr 2nd 2015 09:24 AM jjppof Electricity and Magnetism 1 May 2nd 2013 09:35 AM yungman Advanced Electricity and Magnetism 6 Jun 5th 2011 10:55 PM 