A charge -q is placed at the axis of a charged ring of radius at a distance of `2sqrt(2)` r as show in figure . If ring is fixed and carrying charge Q, the kinetic energy of charge - q when it is relased and reaches the centre of ring will be `(qQ)/(n pi epsi_(0)r)`.Find n

Explanation

K.E. of -q at `0=q(V_0-V_p)`
`=q[Q/(4 pi e_0r) - Q/(4 pi e_0 sqrt(r^2+Q sqrt2 r^2))^2]`
`2/3 (qQ)/(4 pi e_0 r) =(q Q)/(6 pi e_0 r)`