Curved Mirrors The most common type of curved mirror is a spherical mirror A spherical mirror has...
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Transcript of Curved Mirrors The most common type of curved mirror is a spherical mirror A spherical mirror has...
Curved Mirrors
• The most common type of curved mirror is a spherical mirror
• A spherical mirror has the shape of a section from the surface of a sphere
Curved Mirrors
• Concave mirror – the inside surface of the mirror is polished• Convex mirror – the outside surface
of the mirror is polished
Curved Mirrors• Law of Reflection still applies! • angle of incidence = angle of reflection• The normal line is drawn perpendicular
to the mirror at the point of incidence.
Concave Mirrors
• C is the center of curvature• R is the radius of curvature (distance
between C and the mirror)• Principal axis – a straight line drawn
through C and the midpoint of the mirror
Concave Mirrors
• If the object is infinitely far from the mirror, the rays are parallel to each other and the principal axis• These rays reflect from the mirror and
pass through the focal point, F • f- focal length is the distance from F to
the mirror
Concave Mirrors
• F is halfway between C and the middle of the mirror• f=1/2R
Convex Mirrors
• F is halfway between C and the middle of the mirror• f=-1/2R• by convention, we use a negative sign
for the focal length of a convex mirror
The formation of images by mirrors
• Light rays emanate from an object, strike the mirror, reflect from it, and form an image.• Ray Tracing is a graphical method of
analyzing the image produced by either concave or convex mirrors.
CONCAVE MIRRORS
• RAY1: The ray emanates from the object parallel to the principal axis. It strikes the mirror and reflects through the focal point.
CONCAVE MIRRORS
• RAY2: The ray emanates from the object and passes through the focal point. It strikes the mirror and reflects back parallel to the principal axis.
CONCAVE MIRRORS
• RAY3: The ray travels along a line that passes through the center of curvature, C, strikes the mirror and reflects back on itself.
CONCAVE MIRRORS
• If Rays 1,2 and 3 are superimposed on a scale drawing, they converge at a point that defines the top of the image.
CONVEX MIRRORS• RAY1: The ray emanates from the object
parallel to the principal axis. It strikes the mirror and reflects but appears to originate from the focal point F
CONVEX MIRRORS• RAY2: The ray emanates from the object
and heads towards F, reflecting parallel to the principal axis after reflection.
CONVEX MIRRORS• RAY3: The ray emanates from the object
and heads towards C, reflecting back on itself.
CONVEX MIRRORS• The 3 rays appear to come from a point
on a virtual image behind the convex mirror.