In the assembly as shown below, the potential difference across the plates is 4 volts.A positive particle of charge +4e is projected from the negative plate with an initial kinetic energy of 4ev and the negative particle of charge (-2e) is projected from the positive plate.Both the particles reach point 'A' with zero kinetic energy.Find the initial kinetic energy of the negative particle in eV.

Explanation

For the positive particle , applying energy conservation initially and at a point A
`K.E._1+P.E._1=K.E._1+P.E._1`
`implies 4eV+(+4e)(0V)=0+(+4e)(x "volt") " " (x="potential at point A")`
`implies x=1` volt
Now applying energy conservation for the negative particle at point 'A' and initially
`implies K.E._1+(-2e)(4V)=0+(-2e)(1"volt")`
`K.E._1-8eV=-2eV`
`implies K.E._1=6eV`