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Two points charges,each of the 3 into 10 to the power minus 9 c. located at two. virtices of an equilateral triangle of 20 cm how much work must be done to bring a charge of the third corner of triangle from the infiniti |
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Answer» Let a be the side of EQUILATERAL triangle.Initial the potential energy of the SYSTEM is U i = 4πϵ 0 1 r 12 q 1 q 2 = 4πϵ 0 1 aqq =UWhen another charge charge q bring at the third vertex of triangle, the potential energy of the system is U f = 4πϵ 0 1 r 12 q 1 q 2 + 4πϵ 0 1 r 13 q 1 q 3 + 4πϵ 0 1 r 23 q 2 q 3 = 4πϵ 0 1 aqq + 4πϵ 0 1 aqq + 4πϵ 0 1 aqq = 4πϵ 0 1 a3qq =3UThe WORK done = change in potential energy =U f −U i =3U−U=2U |
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