Transcript Document

Reflection and Refraction
Angle of incidence =
angle of reflection
THE LAW OF REFLECTION
• The angle of incidence
is equal to the angle of
reflection.
• The image in a plane
mirror is virtual and is
the same size as the
object.
• Plane mirrors are used
in periscopes.
• They are used in rear
view mirrors.
• The image is as far
behind the mirror is as
the object is in front.
• Image is laterally
inverted
PERISCOPES
Shiny smooth surfaces reflect regularly,
other surfaces also reflect light but if the
surface is rough the light is reflected in
all directions. We call this diffuse
reflection.
Diffuse Reflection
CONVE
X AND
CONCA
VE
MIRRO
RS
Convex and Concave Mirrors
•A concave mirror is a converging
mirror. Parallel rays of light are
reflected through the focal point of
a concave mirror.
•A convex mirror is a diverging
mirror. Parallel rays of light are
reflected so that they appear to
come from the focal point of a
convex mirror.
Uses of Concave Mirrors
• Used to collect light energy, sound,
heat, radiation, radar and TV
signals.
• If you move close to a concave
mirror, then you see a magnified
image of yourself. This image is
upright and virtual as well as
magnified. Shaving and make up
mirrors
Uses of Convex Mirrors
• They always produce virtual upright
images.
• The image is always smaller than the
object.
• They are useful when you want a wide
field of view – car driving mirrors or
shop security.
• This is the bending of light rays
• Happens because the rays change
speed.
• When they enter a more dense
medium (glass, water,) they slow
down.
• When they enter a less dense
medium – like air, they speed up.
Total internal reflection
and refraction
• When an object is viewed
through water the image
we see is changed
because of the way light
waves behave as they
pass from the water into
the air.