A plane mirror is a flat, smooth surface
from which light is reflected by regular reflection
rather than by diffuse reflection.
This means that light rays are reflected with equal
angles of incidence and reflection.
Reflection of light waves from a smooth surface is regular
reflection.
A brick wall has an uneven surface that causes incoming
parallel light waves to be reflected in many directions.
Reflection of light from a rough surface is diffuse
reflection.
DIFFUSE REFLECTION
An object is a source of spreading, or diverging, light
rays.
Every point on an object is a source of diverging light
rays.
The image formed in a plane mirror is the same size as
the object and is the same distance behind the mirror
as the object is in front.
A concave mirror reflects light from its inner (“caved in”)
surface.
In a spherical concave mirror, the mirror is part of the
inner surface of a hollow sphere
The sphere of radius r has a geometric center, C.
FOCAL POINT
CENTER OF SPHERE
r IS THE RADIUS OF
SPHERE
f IS THE FOCAL LENGTH
2f = r THE RADIUS OF
THE SPHERE
OR
OR
DRAW A RAY DIAGRAM
A concave mirror has a radius of curvature of
12.0 cm. An object, 2.0 cm high, is placed 18.0
cm from the mirror.
DRAW A RAY DIAGRAM
A concave mirror has a radius of curvature of
12.0 cm. An object, 2.0 cm high, is placed 18.0
cm from the mirror.
2
18
12
6
Types of Lenses
Each of the lens’s two faces is part of a sphere and can be convex,
concave, or flat. A lens is called a convex lens if it is thicker at the center
than at the edges. Convex lenses are converging lenses because they
refract parallel light rays so that the light rays meet.
A concave lens is thinner in the middle than at the edges and is called a
diverging lens because rays passing through it spread out.