Two positive charges of magnitude $q$ are placed at the ends of a side $1$ of a square of side $2a$. Two negative charges of the same magnitude are kept at the other corners. Starting from rest, if a charge $Q$, moves from the middle of side $1$ to the centre of square, its kinetic energy at the centre of square is

  • [AIEEE 2011]
  • A

    $\frac{1}{{4\pi \,\,{\varepsilon_{0}}}}\,\frac{{2qQ}}{a}\,\left( {1\,\, - \,\frac{1}{{\sqrt 5 }}} \right)$

  • B

    $zero$

  • C

    $\frac{1}{{4\pi \,\,{\varepsilon_{0}}}}\,\frac{{2qQ}}{a}\,\,\left( {1\,\, + \,\,\frac{1}{{\sqrt 5 }}} \right)$

  • D

    $\frac{1}{{4\pi \,\,{ \varepsilon_{0}}}}\,\frac{{2qQ}}{a}\,\left( {1\,\, - \,\frac{2}{{\sqrt 5 }}} \right)$

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  • [AIPMT 2005]

Three particles, each having a charge of $10\,\mu C$ are placed at the corners of an equilateral triangle of side $10\,cm$. The electrostatic potential energy of the system is.....$J$ (Given $\frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}\,N - {m^2}/{C^2}$)

Assertion : Electric potential and electric potential energy are different quantities.

Reason : For a system of positive test charge and point charge electric potential energy $=$ electric potential.

  • [AIIMS 2017]

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