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NEET2013PhysicsElectrostaticsActual

A charge ' q ' is placed at the centre of the line joining two equal charges ' Q '. The system of three charges will be in equilibrium if ' q ' is equal to:

Options

  1. A-Q / 4
  2. BQ / 4
  3. C-Q / 2
  4. DQ / 2

Correct answer

A. -Q / 4

Step-by-step solution

According to the question for equilibrium, net force on charge Q=0 1 4 ₀ Qq r^2 + 1 4 ₀ Q ^2 ( r 2 )^2 =0 aligned & & 1 4 ₀ Q ₂ r^2 & =- 1 4 ₀ 4 Q q r^2 & & Q & =-4 q & & q & =- Q 4 aligned

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