curved mirrors ray diagrams basics mirror equations
TRANSCRIPT
Curved Mirrors
Ray Diagrams Basics
Mirror Equations
Concave Mirrors Focal point is …
½ way between Center (Radius) of Curvature & Mirror
in front of the mirror
Ray Diagrams for Concave Mirrors
Parallel Ray Start from top
of object Goes parallel to
axis & hits mirror
Reflects off mirror through focal point.
Focal Ray Start from top
of object Goes through
focal point & hits mirror
Reflects off mirror parallel to axis
Center Ray Start from top of
object Goes through
center of curvature
Reflects off mirror back through center
Image Top of the Image
is formed at intersection of the three rays
Bottom is on the axis
Image is:•Smaller•Inverted•Real
Convex Mirrors Focal point is…
½ way between Center (Radius) of Curvature & Mirror
behind the mirror
Ray Diagrams for Convex Mirrors Parallel Ray
Start from top of object
Goes parallel to axis & hits mirror
Reflects off mirror lined up with focal pt.
Focal Ray Start from
top of object Aimed at
focal point & hits mirror
Reflects off mirror parallel to axis
Center Ray Start from
top of object Goes
through center of curvature
Reflects off mirror back through center
Image Three Rays do
not meet in the “Real World”
Trace reflections back into “Mirror (Virtual) World”
Image formed at intersection of rays in “Mirror World”
Image is:•Smaller•Upright•Virtual
Mirror Equations Mirror Equations:
(1/do)+ (1/di) = (1/f) f is positive for Concave mirrors f is negative for Convex mirrors di is positive for Real images (in front of Mirror) di is negative for Virtual Images (Behind Mirror)
C = 2f Magnification (Hi, Ho, Di, Do its off to
physics we go…) (hi/ho) = - (di/do) = M
Di/Do
+ in front of mirror
- behind mirror Hi
+ upright - inverted
M + upright - inverted
f + in front of
mirror - behind mirror
Objects and Images @ infinity
On object on the horizon… i.e. the sun Is very far away Assume do = ∞ 1/do = 1/∞ = 0
Images at infinity 1/di = 1/∞ = 0
Concave Mirrors Practice(1/do)+ (1/di) = (1/f)
(1/21)+ (1/di) = (1/7)
1/di = 0.095
di = 10.5
hi/ho = - di/do = M
hi/6 = 10.5/21 = M
M = - 0.5
hi = - 3 cm
21 cm 14 cm
6 cm
Image is:•Smaller•Inverted•Real
Homework
Pg. 659 #7 & 8
Ray Diagram Worksheet