A shunt DC motor operates with:

Speed, n$=1000$rpmn $=1000\backslash ,\backslash$text$\{$rpm$\}$n$=1000$rpm

Generated EMF, Ef$=500$VE$\_$f $=500\backslash ,\backslash$text$\{$V$\}$Ef$=500$V

Field current, If$=1$AI$\_$f $=1\backslash ,\backslash$text$\{$A$\}$If$=1$A

If the field current IfI$\_$fIf$$ is increased to $1\mathrm{.}5$A$1\mathrm{.}5\backslash ,\backslash$text$\{$A$\}1\mathrm{.}5$A while EfE$\_$fEf$$ remains constant, what will be the new speed nnn$?$