An electromagnetic wave has an electric field given by

E$($y$,$t$)=[3\mathrm{.}40105$V$/$mcos$($ky$(1\mathrm{.}3751013$rad$/$s$)$t$)]$k$^$E$($y$,$t$)=[3\mathrm{.}40105$V$/$mcos$($ky$(1\mathrm{.}3751013$rad$/$s$)$t$)]$k$^.$