A charge ` +Q` is uniformly distributed over a thin ring with radius ` R`. A negative point charge `-Q` and mass `m` starts from rest at a point far away from the centre of the ring and moves towards the centre. Find the velocity of this particle at the moment it passes through the centre of the ring .

Answer

`sqrt((2KQ^(2))/(mR))`

Explanation

COME : `K_(f)+U_(i)=K_(f)+U_(f)`

`0+0=1/2 mV^(2)-(KQ^(2))/(R)`
`V=sqrt((2KQ^(2))/(mR))`