An elementary particle of mass 'm' and charge `+e` initially at a very large distance is projected with velocity 'v' at a much more massive particle of charge `+Ze` at rest. The closest possible distance of approach of the incident particle is .

Explanation

For an elementary particle , mass = m, charge `=+e`, velocity `=v`.
For much more massive particle , charge `=+Ze`.
From law of conservation of energy, we have K.E. of elementary particles = Electrostatic potenital energy of elementary particle at a closest distance (d)
`rArr E_(K)=E_(P)`
`(1)/(2)mv^2=(1)/(4pi epsi _(0))xx(zexxexxd)/(d^2)`

`therefore` T he closest possible distance of approach of the incident particle,
`d=(Ze^2)/(2piepsi_(0)mv^2)`