Truecrypt Volume Size - Question

I think I found the answer elsewhere on this site, but it wasn't too clear...so I'd like to confirm here, please.

If I create a TC volume that is 10MB in size, it takes that much space from my hard drive, right? So, if I only use 2MB, then there is no way for anyone to know that? Further, if I use the hidden volume, and add another 2MB for a total of 4MB used, there is no way to tell? So, if forced to give up a password, I can give up the pass for the outer data that is only 2MB, and the party viewing the data would never know that another 2MB was being used in the hidden volume?

Thanks a bunch!

If anyone cares to elaborate, assuming I am correct, could you explain in layman's terms how TC hides unused data in the volume?

 

You've got it.

And a TrueCrypt container is filled completely with random data, then the filesystem is overlaid on top of that.