if a tree fell in the woods?

[Melissa L Overmire <movermir@MAILER.FSU.EDU>]

Dear reference gurus and brainy types alike,
A teacher has asked me to find out what the word is that describes a
question with no answer?
I.E. If a tree fell in the woods and no one was there to hear it would it
make a sound? or What is the sound of one hand clapping? I know, this
makes no sense.  HE seems (the teacher) to think that there is a word for
questions like those. Have no idea where to look, I am stumped!
reply to movermir@mailer.fsu.edu
Thanks
M.Overmire