Summary of mirrors and lenses

The mirror/lens equation:

The magnification equation(s):

SIGN CONVENTIONS:

For a mirror or lens, the light rays come into the optical device from one side; let�s call this the �IN� side.� The light rays leave the mirror or lens on the �OUT� side.� For a mirror, the �OUT� side is the same side as the �IN� side; for a lens, it�s the opposite.

Object on the �IN� side	dobj > 0
��������� (not on the �IN� side)	dobj < 0
Image on the �OUT� side	dimg > 0
��������� (not on the �OUT� side)	dimg < 0
Focus on the �OUT� side	f > 0���� (concave mirrors, converging lens)
��������� (not on the �OUT� side)	f < 0���� (convex mirrors, diverging lens)

VOCABULARY WORDS:

d_obj, d_img > 0:�� REAL object, image

d_obj, d_img < 0:�� VIRTUAL object, image

M > 0: ���������� UPRIGHT

M < 0: ���������� INVERTED

| M | < 1:� ������� SMALLER

| M | = 1:� ������� SAME SIZE

| M | > 1:� ������� LARGER

You only get �virtual objects� if the object for one lens (or mirror) is the image from another lens (or mirror), which is arranged so that d_obj < 0 for the 2^nd imaging device.� See section 26.9, which will be discussed Monday March 26.