Question

a particle of mass m and charge -q circulates around a fixed charge q in a circle of radius r under electrostatic force .the total energy of the system is

Answer 1

If the charge particle is moving in an circular path, then the electrostatic force will balances the necessary centrifugal force.

Therefore, In Equilibrium,

  Centrifugal force = Electrostatic force

   mv²/r = kQ₁Q₂/r²

  1/2 mv² = kQ₁Q₂/r

   $\Big[K.E. = kQ_1Q_2/r \Big]$

Potential energy of the charge = -KQ₁Q₂/r

Total energy of the system = Kinetic energy + Potential energy

 = 0

Hence, total energy of the system is 0.

Hope it helps.