Two charged particles having charge `1 muC` and `-muC` and of mass `50 gm` each are held ar rest while their separtion is `2m`. Find the relative velocity of the particles when their separation is `0.5m`.

Options

A. `(1)/(5)m//s`
B. `(sqrt(3))/(5)m//s`
C. `(3sqrt(3))/(5)m//s`
D. `(3sqrt(3))/(10)m//s`

Answer

C

Explanation

Speed of both will be same at any time.
`(KE + PE)f = (KE + PE)i`
`2((1)/(2)mv^(2)) - (9 xx 10^(9)xx10^(-12))/(0.5) = -(9 xx 10^(9) xx 10^(-12))/(2) + 0`
`mv^(2) = 9 xx 10^(-3) [(1)/(0.5)-(1)/(2)]`
Putting `m = 50//100, v = (3sqrt(3))/(10)m//s`