HW for A (for Wednesday's class). F can do this if you didn't finish it earlier.

Find a formal definition for "focal point" and/or "focal length" of a lens.  Does this apply to all lenses (convex and concave)?

Also, please revisit the hypothesis and tweak it, if you like.

Finally, if you are still unclear about real and virtual images, do a little research about this, too.

As always, this site is helpful:

http://www.physicsclassroom.com/

Also, my apologies for not discussing the hypothesis - when I wrote it on the blog, I forgot to mention that it was optional.  I really didn't want to give you work over Thanksgiving!  Sorry to stress anyone out.