Two identical coaxial rings each of radius R are separated by a distance of `sqrt3R`. They are uniformly charged with charges `+Q` and `-Q` respectively. The minimum kinetic energy with which a charged particle (charge `+q`) should be projected from the centre of the negatively charged ring along the axis of the rings such that it reaches the centre of the positively charged ring is

Options

A. `(Qq)/(4piepsilon_0R)`
B. `(Qq)/2piepsilon_0R)`
C. `(Qq)/(8piepsilon_0R)`
D. `(3Qq)/(4piepsilon_0R)`

Answer

A

Explanation

k_(C_1)+U_(C_1)=k_(C_2)+U_(C_2)`
`k_(min)+qV_(C_1)=0+qV_(C_2)`…i
`V_(C_1)=1/(4piepsilonP_0) (Q/(2R)-Q/R)`
`V_(C_2)=1/(4piepsilon_0)(Q/R-Q/(2R))`
substituting thes value in eq. in we can find `K_(min)`