Phys223 Equations for Chapters 23 and 24 Reflection: i   r Mirror/Thin Lens Equation 1
1
1

 f do di
Refraction: n1 sin 1  n2 sin  2 n
c
v
Glasses: Lens power P 
Lens Maker’s Equation 1
diopters f
1 1 
1
  n  1    f
 R1 R2 
Sign Conventions The mirror equation and the thin lens equation work for both convex and concave mirrors and lenses if you use the correct sign conventions. Mirrors Quantity Positive when Negative when Object location do object is in front of mirror object is in back of mirror (real object) (virtual object) Image location di image is in front of mirror image is in back of mirror (real image) (virtual image) Image height hi image is upright image is inverted Focal length f and radius R mirror is concave mirror is convex Magnification M image is upright image is inverted Thin Lenses Quantity Object location do Image location di Image height hi R1 and R2 Focal length f Magnification Positive when object is in front of lens (real object) image is in back of lens (real image) image is upright center of curvature is in back of lens converging lens image is upright Negative when object is in back of lens (virtual object) image is in front of lens (virtual image) image is inverted center of curvature is in front of lens diverging lens image is inverted Phys223 Equations for Chapters 23 and 24