A proton enters the uniform electric field produced by the two charged plates shown in the figure. The plate

length is $L=12\mathrm{.}0cm.$ The magnitude of the electric field is $2\mathrm{.}5{10}^6\frac{N}{C},$ and the speed of the proton

when it enters is $1\mathrm{.}1{10}^7\frac{m}{s}.$

What distance $d$ has the proton been deflected downward when it leaves the plates? Give you answer in

units of $mm.$