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COMEDK2014PhysicsElectrostatics

Three charges -q,+Q and -q are placed at equal distances along a straight line. If the total P E of the system is zero, then the ratio Q / q becomes

Options

  1. A1 8
  2. B1 6
  3. C1 4
  4. D1 2

Correct answer

C. 1 4

Step-by-step solution

The given situation is shown below Total potential energy of the system =0 1 4 ₀ [ (-q) Q a + (+Q)(-q) a + (-q)(-q) 2 a ]=0 aligned & - q Q a - q Q a + q² 2 a =0 2 q Q a = q² 2 a & 2 Q= q 2 Q q = 1 4 aligned

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