23.1 Mirrors

MIRRORS
Real vs Virtual Images	• A real image forms if and where light rays really intersect. • A virtual image forms if light rays do not intersect, but rather appear to originate from a common point.
Upright vs Inverted Images	• If the image forms on the same side of the principal axis as the object, the image is upright. • If the image forms on the opposite side of the principal axis as the object, the image is inverted.
Plane Mirrors
• The image is located behind the mirror. • Image distance = object distance • The image is virtual, upright, and m = 1. • Image has apparent left-right reversal.
Spherical Mirrors
Focal Length	f = ½R R = radius of curvature
Mirror Equation	1/p + 1/q = 1/f p = object distance q = image distance • When q > 0, the image is real. • When q < 0, the image is virtual.
Magnification	m = h_i / h_o = -q / p h_i = image height h_o = object height • When m > 0, the image is upright. • When m < 0, the image is inverted. • When \|m\| > 1, the image is larger than the object. • When \|m\| < 1, the image is smaller than the object.

PRINCIPAL RAYS (Spherical Mirrors)
Incident Ray	Reflected Ray
Parallel to the Principal Axis	Through the Focal Point
Through the Focal Point	Parallel to the Principal Axis
To the Principal Axis (Center)	θ_incidence = θ_reflection

CONCAVE MIRROR (CONVERGING)
p > f	p < f
• Real, Inverted Images • Magnification increases as p approaches f	• Virtual, Upright Images • \|m\| > 1
CONVEX MIRROR (DIVERGING)
• Virtual, Upright Images • m > 0, m < 1 • f < 0