Unformatted text preview: E = kq/r2 for point charges, E 1 = k(1 x 106 /1.05 2 – 2 x 106 / 1.00 2 + 1 x106 /0.95 2 ) = 135.56 N/C E 2 = k(1 x 106 /2.05 2 – 2 x 106 /2.00 2 + 1 x 106 /1.95 2 ) = 8.45 N/C 5. If E is proportional to 1/R n , then E 1 /E 2 = (1/R 1 n )/(1/R 2 n ) = (R 2 /R 1 ) n . As R 2 = 2R 1 this says E 1 /E 2 = 2 n = 16 suggesting n = 4. 6. As E points away from + charge and toward – charge, at the center of the square all four E’s point toward the bottom of the square at a 45 o angle to the vertical. So E total = 4 x (k x 2 x 106 /(√2/2) 2 )x cos 45 o = 102 x 10 3 N/C pointing down. 7. However V has no direction so in the kq/r terms the +q’s and the –q’s cancel so V = 0....
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This note was uploaded on 02/02/2009 for the course PHYS 10a taught by Professor Martens during the Spring '07 term at Brandeis.
 Spring '07
 Martens
 Charge

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