'(<a href="http://www.j-archive.com/media/2005-02-04_DJ_04.jpg" target="_blank">Sarah of the Clue Crew stands at a blackboard with curved mirrors depicted.</a>)  For a concave mirror this point is in front of it; for a convex mirror, behind it, and expressed as a negative number'
a focal point (or focus)
PHYSICS: For a concave mirror this point is in front of it; for a convex mirror, behind it, and expressed as a negative number
For a concave mirror this point is in front of it; for a convex mirror, behind it, and expressed as a negative number
For a concave mirror this point is in front of it; for a convex mirror, behind it, and expressed as a negative number
PHYSICS
a focal point or focus
PHYSICS