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Reflection & Mirrors
Reflection of Light Rays
To show how light reflection, you can represent light waves
as straight lines called rays.
Regular reflection - parallel rays hit a smooth surface; all
rays reflect at the same angle ---> sharp reflection
Diffuse reflection - parallel rays hit an uneven surface;
each ray hits the surface at a different angle ---> no clear
reflection
Question: Why do we see most objects by diffuse
reflection?
Plane Mirrors
Plane mirror - flat sheet of glass that has a smooth, silvercolored coating on one side
When light strikes a mirror, the coating reflects the light to
form a clear image.
Image - copy of an object formed by reflected or refracted
rays of light
Plane mirrors produce virtual images that is upright and
about the same size of the object.
Question: Why is the image called "virtual"?
When you see your virtual image in a plane mirror, how is it similar to the real you?
Different?
Concave Mirrors
A mirror with a surface that curves inward is a concave
mirror.
The optical axis divides a mirror in half and the rays of
light are parallel to it.
The point at which rays parallel to the optical axis meet is
the focal point.
The type of image formed depends on the location of the
object.
These mirrors can form either virtual images
or real images.
Real images form when rays actually meet,
are upside down, and may be larger or smaller
than the object.
Question: Why are parallel rays no
longer parallel after they are reflected by
the concave surface of the mirror?
Convex Mirrors
A mirror with a surface that curves outward is a convex
mirror.
The rays spread out but appear to come from a focal point
behind the mirror.
The rays never meet, so the images are ALWAYS virtual
and smaller than the object.
Question: Why does a convex mirror never produce a real image?
What are examples of convex mirrors you use?