Reflection and Mirrors by hedongchenchen


									Reflection and Mirrors

        Seeing Yourself
        Law of Reflection
The law of reflection states that the angle of
 incidence is equal to the angle of reflection.
Incident ray is the
ray moving toward
the surface
Reflected ray is the
ray moving from the
Normal is an
imaginary line
perpendicular to the
         More Definitions
Angle of incidence
is the angle
between the
incident ray and
the normal
Angle of reflection
is the angle
between the
reflected ray and
the normal
           Regular Reflection
 Rays of light hit
a smooth
surface. The
reflected rays
bounce off the
surface parallel
to each other.
        Diffuse Reflection
Rays of light hit a
rough surface. The
reflected rays are
not parallel to each
other when they
bounce off the
An Image is the point where extended
reflected rays of light intersect.
Real image—formed by converging light rays
and can be displayed on a screen
Virtual Image—an image that can be seen by
the observer but cannot be projected on a
screen because light from the object does not
actually come to a focus.
             Plane Mirrors
Image is the same size
as the object
Image is the same
distance behind the
mirror as the object is
in front of the mirror.
The front and back of
image of are reversed.
Virtual image.
           Ray Diagrams
A ray diagram is a diagram which traces the
path which light takes in order for a person to
view a point on the image of an object. On the
diagram, rays (lines with arrows) are drawn
for the incident ray and the reflected ray.
             Concave Mirrors
Concave mirrors are
shaped like the inside of a
Parallel rays of light are
reflected towards a single
point—the focal point
The real image is inverted
and in front of the mirror.
The virtual image is erect
and behind the mirror.
   Image from a concave mirror
 depends on the placement of the
  object in relation to the mirror
           Convex Mirrors
A convex mirror is
shaped like the outside
bottom of a spoon.
Convex mirrors produce
an erect virtual image
behind the mirror.
Convex mirrors are used
as rearview mirrors in
cars and in stores to
observe shoppers.
       Spherical Aberration
Curved mirrors that are
made from part of a
sphere do not reflect all
rays of light through the
focal point.
Parabolic mirrors are
used when a sharp
focus is needed—they
do not have spherical
         The Mirror Equation
f is the focal length
(distance from mirror to
focal point)
do is the distance from
the mirror to the object
di is the distance from the
mirror to the image
The focal length of a
curved mirror is ½ of the
radius of curvature.
     Magnification Equation
m is the magnification
Positive m represents
an erect image
Negative m represents
an inverted image
hi is the image height
h0 is the object height
di is the image distance
do is the object distance

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