Optics: Refraction of Light in Lenses

1. Prepared by:
Ms. Jasmine Nikki M. Versoza

2. LENSES
▪ Smoothly curved
transparent materials
usually made of glass or
plastic
▪ Has one or two curved
surfaces

3. CONVEX LENSES
▪ Converging lenses
▪ Parallel rays are refracted
towards the thick part of the
lens and converge on the
other side

4. CONCAVE LENSES
▪ Diverging lenses
▪ Parallel rays are refracted
towards the thick part of the
lens and diverge on the
other side

5. PARTS OF A LENS
▪ Principal axis- imaginary
line passing through the
center of the lens
▪ Lens axis- imaginary line
which bisects the
symmetrical lens into two

6. LENS AXIS
OPTICAL
CENTER
PRINCIPAL
FOCUS
PRINCIPAL
AXIS

7. CONVEX LENS
F
F
f

8. CONCAVE LENS
F
F
f

9. FOCAL LENGTH (f)
Distance from the
principal focus to the
center of the lens

10. LOCATING THE IMAGE
GRAPHICALLY
CONVEX LENS
1.The ray from the object parallel to the
principal axis. This ray passes through the
focus after refraction. This is ray 1.
2. The ray passing through the center of the
lens. This ray is not refracted. This is ray 2.
3.This ray passes through the focus from
the object and is refracted parallel to the
principal axis. This is ray 3.

11. F
F
Ray 1
Ray 2
Ray 3
object
image

12. LOCATING THE IMAGE
GRAPHICALLY
CONCAVE LENS
1.The refracted ray comes from the
focus. This is ray 1 coming from the
object.
2. The ray passing through the center
of the lens. This ray is not refracted.
This is ray 2.

13. F
F
object image
Ray 1
Ray 2

14. LOST
L- location (image distance)
O- orientation (upright or
inverted)
S- size (reduced or enlarged)
T- type of image (real or
virtual)

15. EXERCISES
1.Locate the images of the
objects indicated in each
figure using ray diagrams.
2.Summarize your findings
using a table 1.0

16. Location of
object
L O S T
a. Between 1f
and lens
b. At the focal
length 1f
c. Between 1f
and 2f
d. At 2f
e. Beyond 2f