A “Visual” Review

Fuss Physical Science

How do you locate the image in a Curved Mirror Situation.

Pick a point on the object (usually the one furthest from the principal axis), and then draw 2 intersecting rays that obey the following rules:

1. Any ray parallel to the principal axis is reflected through the focus.

2. Any ray through the focus is reflected parallel to the principal axis.

3. Any ray through the center of curvature is reflected back along the incident ray (back along itself)

Concave/Converging

Mirrors

C F

Moving towards the focus, the image is REAL, inverted. It could be smaller, the same size, or larger than the image (depending on the object location)

“OUTSIDE“ the focus

Concave/Converging

Mirrors

C F

NO IMAGE !!!!!! The lines never cross!!!!

“ON” the focus

Concave/Converging Mirrors

C F

“INSIDE” the focus

Moving towards the mirror, the image is VIRTUAL, UPRIGHT, and gets smaller (although the image is ALWAYS larger than the object itself).

Convex/Diverging Mirrors

F C

When an object gets closer to the mirror, its image is VIRTUAL, UPRIGHT, and keeps getting smaller (and the images are always smaller than the object).

C’ F’

Note: All rays want to pass through F, but

none do

Concave mirrors

Convex mirrors

Can make small objects appear larger

Can make large objects appear smaller (see a WIDE view)

Make-up mirrors, shaving mirrors

Security mirrors, Driveway mirrors, Car door mirrors

LENSES

Fuss Physical Science

How do you locate the image formed in a LENSE Situation.

1. Any ray parallel to the principal axis is reflected through the focus.

2. Any ray through the focus is reflected parallel to the principal axis.

3. Any ray through the center of the lens passes directly through the lense following its same path.

Image Formation in CONVERGING Lenses

F’

F

Image Formation in Diverging Lenses

F

F’

Cameras ……

….. and the human eye

BOTH use converging lenses with the object far beyond the focus

and both form INVERTED images.

Film

NOT ON TEST, BUT ON FINAL EXAM!!!!

Magnifying Glasses

2F’ F’ F 2F

Object that you are looking at (under the lens)

Larger, virtual image that you see

Film ProjectorsW

hite screen

The Human EyeCornea: Protective “Window” of

eye

Iris: Colored part that acts like a

camera shutter.

Pupil: Hole in the middle of the

iris.

Lens: has adjustable focal length.

Retina: Where image is formed.

Optic nerve: Sends image to

brain where it is flipped

upside down.

Muscles that “tense” the lens

Furthest Point that the eye can see

clearly

Far Point

Object beyond the far point can’t be focused

clearly on the retina b/c lines cross too soon

Diverging Lens makes the light rays cross further away (on the retina) allowing you

to see a clear image.

Far-Sightedness

Closest Point that the eye can see clearly

Near Point

Object inside the near point can’t be focused

clearly on the retina b/c light rays cross too late

Converging Lens makes the light rays cross sooner,

allowing a clear image to form on the retina

Focus of lens