# Long space in italic format

MWE,

\documentclass[a4paper,11pt]{article}
\usepackage[utf8]{inputenc}
\begin{document}
120 kHz ’e

\textit{120 kHz ’e}
\end{document}


and output,

Sometimes this red line is getting longer. Why not red line is short? I didn't find solution about this question. Does anyone know how to fix it? (My english text changeable)

(SI) Units have to be typed according to certain rules. Don't worry about them if you don't know what are the rules, use siunitx. Then all the spacing and fonts will come right. Never use italics for units as already told by egreg.

\documentclass[a4paper,11pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[detect-all]{siunitx}
\begin{document}
\SI{120}{\kHz}\,’e

!!!Don't do this!!!
\textit{\SI{120}{\kHz}\,’e}   %% Don't do this don't.

\end{document}


• Probably the space before 'e should be absent or thin (\,); I believe it's a “declension suffix”. – egreg Apr 15 '15 at 23:43
• @egreg Thanks, I wasn't aware of that. BTW what is declension suffix? Reading now :-) Thanks and I have added a thin space. – user11232 Apr 15 '15 at 23:47
• Possibly something analog to this question: tex.stackexchange.com/questions/98330/… I'm not sure if “declension” is the right term. – egreg Apr 15 '15 at 23:49
• @egreg Oh, now I am slowly getting it. Then I think it should be 120'e kHz IMO. Thanks for letting me learn some Latin things. :-) – user11232 Apr 15 '15 at 23:52
• That's Turkish. ;-) – egreg Apr 15 '15 at 23:55