Reflection in Curved Mirrors. - Terminology Focal Point Ray Diagrams – Concave Mirrors - Properties of a Converging Mirror - Uses of Concave Mirrors Focal Point – Convex Mirror Images in a Convex Mirror - Uses of Convex Mirrors. Terminology. - PowerPoint PPT Presentation
Reflection in Curved Mirrors- Terminology Focal Point Ray
Diagrams Concave Mirrors- Properties of a Converging Mirror - Uses
of Concave Mirrors Focal Point Convex Mirror Images in a Convex
Mirror- Uses of Convex Mirrors
1TerminologyCentre of curvature (C) Middle of the circle Focus
(focal point) (F) Where reflected rays all intersectPrincipal Axis
(PA) The line drawn through the centre of the mirror (and meeting
the mirror at 90) Vertex (V) The exact point where the PA meets the
mirror.
2RecallLight rays always have an Angle of Reflection = Angle of
IncidenceThis equal angle is between the ray and the normal which
is 90 to the mirrors surface at the point where the ray hits the
mirrorAngle of IncidenceAngle of ReflectionNormal (90 to mirror
surface)3TerminologyConcave Mirrors are also known as converging
mirrors as the light converges at the focus in front of the mirror
and creates a real image.Mirror is caved in
Convex Mirrors are also known as diverging mirrors as the focus
is found behind the mirror (virtual image) and is found by tracing
back the reflected rays in a straight line.
4Focal Point Concave MirrorWe can use parallel rays to PA to
find the focal length of a concave mirror.
All parallel lines will reflect into the focal point *note the
normal is 90 to the point on the mirror where the ray strikes
The focal point for a concave mirror is to the left
5Concave Mirror Rules
6Concave Mirror Rules
7Concave Mirror Rules
8Concave Mirror Rules
9Ray Diagrams Concave MirrorsYou need 2 rays to locate an
image.The image is located where the rays intersect.If the rays do
not intersect, you need to trace them back to the point where they
intersect.You need to include 2 basic rays.A parallel ray is
reflected to the mirror then through the focal pointA ray is sent
through the focal point is reflected parallel to the principal
axis.
F10Ray DiagramsDescribing Images
S Size (Larger, Smaller, Same)A Attitude (Upright or inverted)L
Location (How far from the mirror?)T Type (Real or Virtual)
Small than objectInvertedBetween C and FRealF11Object beyond
C
12Object at C
13Object between C and F
14Object at F
15Object between F and mirror
16Concave Mirror Demo
17Properties of a Converging Mirror
18Uses of Concave MirrorsSearchlights, car headlights and
flashlights all use concave mirrors to create parallel or almost
parallel beams of light (Why?)
Telescopes and satellite dishes use concaves mirrors to focus
electromagnetic waves at the focal point (Why?)
19Uses of Concave Mirrors ContWe can also use concave mirrors to
magnify a reflection close up. Why does it give this type of
reflection?
20
Concave Mirror Demo
End of Day 122Reflection In Curved MirrorsDay 2
23RecallLight rays always have an Angle of Reflection = Angle of
IncidenceThis equal angle is between the ray and the normal which
is 90 to the mirrors surface at the point where the ray hits the
mirrorAngle of IncidenceAngle of ReflectionNormal (90 to mirror
surface)24TerminologyConcave Mirrors are also known as converging
mirrors as the light converges at the focus in front of the mirror
and creates a real image.Mirror is caved in
Convex Mirrors are also known as diverging mirrors as the focus
is found behind the mirror (virtual image) and is found by tracing
back the reflected rays in a straight line.
25Focal Point Convex MirrorThe focal point for a convex mirror
is to the right.It can be found by drawing lines parallel to the PA
towards the mirrorExtend the reflected lines past the mirrorWhere
the imaginary lines intercept is the focal point
26Centre of sphere Convex MirrorThe C for a convex mirror is to
the right.It can be found by drawing a line perpendicular to the
mirror at any pointExtend the reflected lines past the mirrorWhere
the imaginary lines intercept the PA is the C
27Convex Mirror RulesThe difference between a concave mirror and
a convex mirror is that in a convex mirror, F (now called a virtual
focus) and C are behind the mirror and light rays seem to come from
an apparent light source behind the mirror
28Convex Mirror Rules
29Convex Mirror Rules
30Convex Mirror Rules
31
Ray Diagrams Convex MirrorsThe image is located where the
extended reflected lines intersect behind the mirrorYou need to
include 2 basic rays.A parallel ray that extends from the top of
the object to the mirror and is reflected back to the viewerA ray
is directed towards the focal point and is reflected parallel to
the principal axis.Extend the reflected rays past the mirror until
they intersectThe point of intersection is the top of the image.
The image extends down to the Principal axis32Images in a Convex
MirrorThe rays reflected off a convex mirror always diverge
Reflected rays from an object never cross in front of the mirror
to form a real image
Instead it ALWAYS creates a smaller, upright, virtual
image33Uses of Convex MirrorsConvex mirrors show a wide range of
view with their smaller virtual image
Used in:Security mirrors Side-view mirrors in carsObjects in
mirror are closer than they appear Explain.
34Convex Mirror Simulation
35
One More DemonstrationConcave vs. Convex Curved Mirrors
36
