1
Session 21: Ra
y Optics
–
R
e
fr
action @
cur
v
ed surf
aces
–
Principal Focii
& Lenses
•
R
ecap
•
Principle f
ocii
•
V
elocity
of
imag
e
•
Lenses (na
tur
e
& types)
•
Lens
mak
er
’
s
f
ormula
•
Rules f
or dr
awing r
a
y diagr
am