A Aliya New member Dec 2, 2009 #1 while we have to determine focal length of a convex lens in lab than in our book it is written that find index correction between image and object needle by placing them at knitting needle distance.I cant understand this step?
while we have to determine focal length of a convex lens in lab than in our book it is written that find index correction between image and object needle by placing them at knitting needle distance.I cant understand this step?
