Magnification in Spherical Mirrors
Magnification (m) is the ratio of the height of the image (h') to the height of the object (h). It can also be expressed as the negative ratio of the image distance (v) to the object distance (u).
m = h'/h = -v/u
Understanding Magnification:
- |m| > 1: Image is larger than the object (enlarged)
- |m| < 1: Image is smaller than the object (diminished)
- |m| = 1: Image is the same size as the object
- m > 0: Image is upright (same orientation as object)
- m < 0: Image is inverted (opposite orientation to object)
Magnification in Concave Mirrors
For a concave mirror, the magnification depends on the object's position:
- Object beyond C: m is negative and less than 1 (inverted, diminished)
- Object at C: m = -1 (inverted, same size)
- Object between C and F: m is negative and greater than 1 (inverted, enlarged)
- Object at F: m is infinite (no image formed)
- Object between F and P: m is positive and greater than 1 (upright, enlarged)
Object Distance (u)
NearFar
u = 150 units
Focal Length (f)
SmallLarge
f = +100 units