Concave/Convex Mirror Image Formation Rules
1.
Parallel Rays - Light rays parallel to the principal axis
are reflected through the focus of the mirror.
2. Focus Rays - Light rays through the focus of the mirror
are reflected parallel to the principal axis.
3. Chief Rays – Light rays through the center of curvature
of the mirror are reflected back along the same path.
4. Vertex Rays – Light rays that strike the mirror at its
vertex leave at the same angle that it entered.
Object Located Beyond f and C.
1
object
4
3
2
C
f
2
image
4
1
3
Concave Mirror Image Formation for an Object Less than f
2
object
C
f
3
1
4
image
Convex Mirror Image Formation
1
3
2
image f
object
4
C
Concave Mirror Image Formation
• Concave Mirror Beyond C
• Concave Mirror Between C and f
• Concave Mirror Image Formation Less than f
Lenses
The focal length for a lens is dependent on both the curvature of the
lens, and the lens material.
Convex Lens (Converging Lens)
f
All light rays parallel to the principal axis converge to the focal point
after passing through the convex lens.
Image Properties
Image Type: Real or Virtual
Image Orientation: Inverted or Erect
Image Height (Size): Smaller, Larger, Same
Image Distance: Closer, Farther, Same
•The image properties of a convex lens are the same as a concave mirror.
Concave Lens (Diverging Lens)
f
Image Properties
Image Type: Virtual
Image Orientation: Erect
Image Size: Smaller
Image Distance: Closer
The light rays parallel to the principal axis refract and diverge after going
through the lens, such that if the refracted light rays are extended backwards,
then the rays would converge at the focal point for the lens.
• The image properties of a concave lens are the same as a convex mirror.
Lens Ray Image Formation Rules
1. Parallel Ray – A light ray parallel to the
principal axis is refracted towards the lens
focus.
2. Focal Ray - A light ray passing through the
focus refracts parallel to the principal axis.
3. Chief Ray – A light passing through the center
of the lens continues traveling along its original
path unaffected by the lens.
Convex Lens Ray Diagram
(Beyond f)
1
1
2
3
image
object
2f
f
f
3
2
2f
Convex Lens Ray Diagram
(Less than f)
2
2
1
image
2f
f
object
1
f
2f
3
Concave Lens Ray Diagram
1
1
object
2
2
3
2f
f
image
f
2f
3
Image Properties Graphic (Converging Instruments)
object
C>do>f,
do>C,
hi>ho,
real
do from ∞
When do=∞,
di=f, hi<<ho,
real
C
f
do=f, di=∞,
no image
When do=C,
di=C,
hi=ho,
real
image
When do<f,
di>do,
hi>ho,
virtual
Convex Mirror Image Formation
do<∞,
di<f,
hi<ho,
virtual
object
image f
do=∞,
di=f,
hi<<ho,
virtual
C
Concave Lens Ray Diagram
object
2f
do<∞,
di<f,
hi<ho,
virtual
f
do=∞,
di=f,
hi<<ho,
virtual
image
f
2f