
BASIC GEOMETRIC OPTICS 45
Mirror
Mirror
Mirror
Mirror
S
S´
R
x
X
S
x
X
S
x
X
S
–x´
X´
S´
–x´
X´
S´
s
–x´
X´
X
θ
θ
V
V
V
r
s´
(A)
(B)
(C)
(D)
Figure 2.10 The curved mirror. The angle of reflection is the same as the angle of incidence
for a ray reflected at the vertex (A). A ray through the center of curvature is reflected normally
(B). These rays intersect to form the image (C). From this construction, the image location and
magnification can be determined (D).
and magnication. The rst ray we choose is the one reected at the vertex, V.Thevertex is
dened as the intersection of the surface with the optical axis. The axis is normal to the mirror
at this point, so the angle of reection