Mirrors

Ch. 20

Mirrors

• Mirror – any smooth object that reflects light to form an image

Mirrors

• Focal Point – light rays all pass through the same point

• Focal Length – distance from center of mirror to focal point

Mirrors• Plane Mirrors –

– Flat surface– Produces upright images– Image appears to be behind the

mirror– Light comes from in front of the

mirror – does not pass through (opaque)

– Virtual image – no light passes through the image

– Distance in front = distance behind

Mirrors

• Concave Mirror• Curved inward, like the

inside of a spoon• Converging rays – come

together

• Depending on where the object is, 3 different things happen:

Mirrors• Object further out than

the focal point (F)– Image will be upside

down and real– Rays meet at image so

you could actually see it

– Hold a screen there and see it

Mirrors

• Object placed in between the focal point (F) and mirror– Image will be upright, enlarged and virtual– Example: hand mirrors

Mirrors

• Object placed at focal point– Concentrated light

beam– No image because

rays don’t converge– Examples:

lighthouse, spotlights

Mirrors

• Convex Mirror– Curves outward– Allow large areas

to be viewed– Diverging rays –

spread out

Mirrors

• Convex Mirrors– Image is virtual,

upright, smaller than original object

– Examples: security mirrors, rear and side view mirrors (objects are closer than they appear)

Mirrors