# A proton is fired towards a positively charged plate located at a distance $x$. As the proton reaches just close to the plate, it stops there. The surface charge density of the plate is $4 \times 10^{−6} C/m^2$. If the proton was fired with the initial kinetic energy of $85\; eV$, then what is the value of distance $x$?

The value of distance $x$ is $1.88 \times 10^{-4} m$