Two identical particles, each having a charge of 2.0 × 10^–4 C and mass of 10g, are kept at a separation of 10 cm and then released. What would be the speeds of the particles when the separation becomes large?

Given:
Charge on two identical particles: q₁=q₂= 2.0 × 10^–4 C
Mass of the two particles : m₁=m₂= m = 10 g = 0.01 kg
Separation between the charges : r = 10 cm = 0.1 m
Formula used:
When they are released, the force of repulsion will be acting on both the particles making them drift apart thereby increasing distance between them.
Potential Energy at the start will be
where U_initial is the initial potential energy between the charges ,k is a constant and k= =9× 10⁹ Nm²C^-2 , q₁ and q₂ are point charges and r is the separation between them.
Final Potential energy would be zero as the particles will gain Kinetic energy and the separation between the charges would approach infinity : U_final = 0
Now by conservation of energy:
Total kinetic energy is :
Where , m is the mass of the particles and V is the velocity gained by the particles.





Hence, when the separation becomes large the speed of the particles should be 600 m/s.