Two parallel conducting grids, Grid X and Grid Y, are placed in a vacuum with electrical potentials of VX=−5.0 VV_{\text{X}} = -5.0\text{ V}VX=−5.0 V and VY=−1.0 VV_{\text{Y}} = -1.0\text{ V}VY=−1.0 V respectively. A charged particle is released from Grid Y and travels directly to Grid X. If the particle gains exactly 8.0 eV8.0\text{ eV}8.0 eV of kinetic energy during this motion, which particle is it?
proton
electron
alpha particle
O2−\text{O}^{2-}O2− ion