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 Electricity and Magnetism Electricity and Magnetism Physics Help Forum Jan 11th 2015, 09:40 AM #1 Member   Join Date: Oct 2013 Posts: 48 Electric field problem Hi all the members, Since this is my first posting here this year, I would like to wish you first a Happy New 2015 Year!!! to all of you Now, the problem: Four charged particles are at the corners of a square of side a(I will try to show it - the right side is pushde to the left when I save the square???). (Let A = 5, B = 5, and C = 5.) qA-------q | | | | | | qB-------qC a) I need to determine the electric field at the location of charge q. (Use the following as necessary: q, a, and ke.) so, since the electric field at charge q will be the sum of the electric fields caused by Aq, Bq and Cq I take it one by one: for Aq, E= k_e*(5q/a^2)i + 0j for Bq, E= k_e*(5q/a^2)[a/sqrt(2a^2)]i + k_e*(5q/a^2)[a/sqrt(2a^2)]j = = k_e*(5q/a^2)[1/sqrt(2)]i + k_e*(5q/a^2)[1/sqrt(2)]j and for Cq, E = 0i + k_e*(5q/a^2)j now, if we sum them all and take the common factor, we get E_total = k_e*(5q/a^2)i + k_e*(5q/a^2)[1/sqrt(2)]i + k_e*(5q/a^2)[1/sqrt(2)]j + k_e*(5q/a^2)j = = k_e*(5q/a^2){1i + [1/sqrt(2)]i + [1/sqrt(2)]j +1j}= = k_e*(5q/a^2){1.707i + 1.707j} = k_e*(q/a^2){12.07} N/C, the magnitude of the electric field Can you please check my work, because my answer is considered as incorrect, and I have no idea why Thanks Last edited by dokrbb; Jan 11th 2015 at 09:43 AM. Reason: the square doesn't keep the right side in place   Jan 11th 2015, 12:34 PM #2 Member   Join Date: Oct 2013 Posts: 48 Never mind; I got it, the mistake was when I was calculating the unit vector for the charge at position B  Tags electric, field, problem 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 puggleboy Electricity and Magnetism 5 Feb 1st 2016 07:41 AM TomM Electricity and Magnetism 1 Apr 18th 2011 04:52 PM jasonlewiz Electricity and Magnetism 0 Jul 23rd 2010 10:19 PM Bobbery7 Electricity and Magnetism 1 Jan 19th 2009 11:38 AM Ess J Electricity and Magnetism 4 Aug 31st 2008 09:31 AM 