de Broglie wave equation
...where
(electron mass =
(1 Joule =
Resolving...
$lambda=(6.626*10^-34 "J"cdot"s")/(mv)$
$lambda=(6.626*10^-34 "J"cdot"s")/((9.109*10^-31 "kg")(2.0*10^8 "m/s"))$
$lambda=(6.626*10^-34 "kg"cdot"m"^2"/s")/(18.2*10^-23 "kg"cdot"m/s")$
Here, everything is cancelled except
$lambda=3.64*10^-12$ $"m"$