Adverbs that act as connectives (joining two sentences) while conveying something or making a query related to time, place, manner, degree, etc., are called Relative Adverbs.
- I am not sure when he will come.
- This is the place where he lives.
- Tell me how efficient she is.
- You know how regularly those volunteers pitch in to help.
- Make up your mind as to when you would want to pay us a visit.