Lenses refract light and focus it at a point. They are made of glass or plastic and have two focal points on either side. Light rays bend as they pass through a lens due to refraction. There are two main types of lenses: convex lenses, which are thicker in the center and focus light, and concave lenses, which are thicker on the edges and diverge light. Convex lenses form real or virtual images depending on the object's position, while concave lenses always form upright, reduced images.

1. Lenses

2. What are lenses?

3. A lens is a transparent
material made of glass
or plastic that refracts
light rays and focuses
(or appear to focus)
them at a point.

4. A lens has two focal points
each on either side

5. How lenses work?

6. Refraction is the
bending of light when it
travels from one
medium to another of
different optical
densities.

7. Light rays bend as they
pass through the lens
resulting to a change n
direction.

8. Types of Lenses
1. Convex lens
2. Concave lens

9. Convex
Lens
• It is thicker
in the center
than edges.

10. Convex Lens
• It forms real images
and virtual images
depending on position
of the object.

11. Convex Lens
It is also called
Converging Lens because
the light that passes
through it tends to
converge at a particular
point called the focal point.

13. Objects appear closer
and larger

14. Concave
Lens
It is thicker at
the edges and
thinner in the
center.

15. Concave Lens
It forms upright and
reduced images.

16. Concave Lens
It is also called Diverging
Lens because the light
that passes through it
tends to diverge at a
particular point called the
focal point.

18. Objects appear
smaller and farther

19. Images Formed by Lenses
In locating the image formed in
lenses graphically, two
important points are considered.

20. Vertex, V – The geometric center of
the lens.
Focal point/ Focus, F – A point where
light rays converge (or appears to
converge) when parallel light rays
pass through a lens. Its distance fro
the vertex is called the focal length

21. Three Most Useful
Rays in Lenses