Ray DiagramsTarget: construct a ray diagram for lenses

Optical centre

Principal axis

Principal focus or focal point

Focal length, f

Object distance, do

Image distance, di

First raySecond ray

Useful Formulae

oi ddf

111

o

i

o

i

d

d

H

Hm 2fSS oi

f = focal lengthdi = distance from image to lens do = distance from object to lens

m = magnificationHi = height of imageHo = height of objectdi = distance from image to lens do = distance from object to lens

f = focal lengthSi = distance from image to focal point So = distance from object to focal point

Target: calculate values from a ray diagram

Descartes’ Formula Newton’s FormulaMagnification