4.4 – convex mirrors p. 318 – 320. how are convex mirrors different from concave ones? both...
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HOW ARE CONVEX MIRRORS DIFFERENT FROM CONCAVE ONES?
Both mirrors are curved Convex is shaped so the
middle of the mirror is pushing out toward you
Convex mirrors are aka diverging mirrors because reflected rays spread apart (diverge)
after hitting the mirror
CONVEX MIRRORS PRODUCE VIRTUAL IMAGES Rules for drawing images produced
in convex mirrors are the same as those for concave mirrors
images that form are always virtual must extend reflected
rays behind the mirror to make them intersect
DRAWING RAY DIAGRAMS F and C are located on the non-
reflective side of the mirror (because it’s a convex mirror)
When drawing ray diagrams, rays touch the top of the object, and then travel to F or C as though the incident or reflected ray travels through F or C but they don’t actually
RULES TO DRAWING A RAY DIAGRAM1. Rays parallel to the PA reflect as if they had
gone through F
2. Rays appearing to pass through F reflect back parallel to the PA (opposite of #1)
3. [Rays that appear to pass through C reflect back along the same path]
p. 320
STEPS: Draw a ray from the top of the object:
1.Parallel to the PA, which reflects off mirror as if it had gone through F
2.As though it will pass through F, which reflects back parallel to the PA (opposite of #1)
3.[As though it will pass through C, which reflects back along the same path]
p. 320
IMAGE CHARACTERISTICS
L – closer to mirror O – upright S – smaller T – virtual (you have to extend the
reflected rays behind the mirror so they intersect)
DIFFERENCES BETWEEN IMAGES FORMED IN CONCAVE & CONVEX MIRRORS
LOST characteristics in convex mirrors are always the same L – closer to mirror O – upright S – smaller T - virtual
LOST characteristics vary in concave mirrors depending on where the object is placed Between mirror & F Between F & C Beyond C
WHAT ARE CONVEX MIRRORS USEFUL FOR? Convex mirrors produce images that are
smaller, but give a wider field of view than in concave mirrors
Used for: safety (car side mirrors and hallways with
sharp, “blind” corners) security (inspecting underneath cars at the
border, in retail stores)
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