Review Sheet: Mirrors

shape

flat mirror

"caved in"

"bowed out"

radius

R = 2f

position of principal focus

- - - -

F is "in front of the mirror"

F is "behind of the mirror"

image
position

d_i = - d_o

1/d_o + 1/d_i = 1/f
do is always positive
d_i is positive if real
d_i is negative if virtual
f is positive if concave

1/d_o + 1/d_i = 1/f
do is always positive
d_i is negative if virtual
f is negative if convex

image
properties

virtual
upright
M = 1

six case ray diagrams
image varies with d_o

d_o Ž Ľ	d_i = f real	M 0
d_o> 2f	2f < d_i < f real	M < 1
d_o= 2f	d_i = 2f real	M = 1
2f < d_o < f	d_i> 2f real	M > 1
d_o= f	no image is formed	- - - -
d_o< f	0 < d_i < - Ľ virtual	M > 1

ray diagrams
virtual, upright, M < 1

d_o Ž Ľ	d_i = -f virtual	M 0
any d_o< Ľ	0 < d_i < -f virtual	M < 1

magnification

M = 1

M = | d_i / d_o | = | I / O |

rays

line up the top/bottom of the eye with the image, draw in a line - solid in the air, dotted behind the mirror, bounce it back to the object. Then put arrows pointing away from the object, to the mirror, and then into the eye.

#1 top of the object, parallel to the axis, strikes the mirror, reflects through F

#2 top of the object, through C, strikes the mirror, reflects back through C

#3 top of the object, passes through F, strikes the mirror, reflects parallel to the axis

#1 top of the object, parallel to the axis, strikes the mirror, lines up with F, reflects back
(dot in line to F)

#2 top of the object, aims for C, strikes the mirror, reflects back (dot in line to C)

#3 top of the object, aims for F, strikes the mirror, reflects parallel to the axis
(dot back parallel reflection)

multiple images of angled plane mirrors

N = (360ş / q) - 1

drop a normal to the first
subscripted mirror
measure d_i = - d_o
draw in the standard rays

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