왜?
why?
어디?
where?
뭐?
what?
어느?
which?
언제?
when?
어떻게?
how?
누가/누구?
who?
어떤?
what kind (of)?
(describes traits, qualities, types; focuses on describing something)
무슨?
what kind (of)?
(asks which one out of many known categories, e.g. specific name, title, category; focuses on specifying and clarifying)
얼마?
how much?
얼마나?
how many?