Geometric Optics

1
Geometric Optics
2
Definitions

• Real Image - Light passes through the image
  point.
• Virtual Image - Light does not pass through the
  image point.
• Magnification
• Negative means the image is inverted.

3
Plane Mirror

• Plane Mirror Properties
• d0 di
• M 1
• Image is virtual and erect
• Image has right-left reversal

4
Spherical Mirror

• Focal Point - Location where parallel incoming
  rays converge or appear to converge.

Image Distance
Magnification
Focal Length
Concave Mirror
Convex Mirror
5
Concave Mirror

• l, l, f, and R are positive values
• Image is inverted and real

6
Convex Mirror

• l is positive
• l, f, and R are negative
• Image is erect and virtual

7
Grocery Shopping

• In a grocery store you see an aisle mirror which
  is convex with a 1.0 m radius of curvature. How
  tall is your image if you are 2.0 m tall and 3.0
  m away from the mirror?

8
Images from Refraction

• Assuming small incidence angle
• Use positive numbers for values when
• l in front of the surface (Real Object)
• l R in back of the surface
• Use negative numbers for values when
• l in back of the surface (Virtual Object)
• l R in front of the surface

9
Fish and the Kitten

• A kitten is located 10 cm from a fish bowl with a
  2.0 m radius of curvature. Where is the image of
  the kitten and tall is it if the kitten is 20 cm
  tall.

10
Thin Lenses

• A lens consists of two refracting surfaces.
• For thin lenses
• Positive
• l in front of the lens, l, R1 and R2 behind
• Negative
• l in back of the lens, l, R1, and R2 in front

R2
R1
11
Thin Lenses

• Convex Lens - Converging
• Concave Lens - Diverging

Parallel Light Rays
focus
Parallel Light Rays
focus
12
Vision Problems
Hyperopia farsightedness Corrected with a
convergent lense.
Myopia nearsightedness Corrected with a
divergent lense.
Diopters m-1
Lens Power
13
Microscope

• Objective and eyepiece separated by a fixed
  distance, L.

Angular Magnification Max M125/f Relaxed
M25/f
Near Point 25 cm
Lateral Magnification M-q/p
L
fe
14
Telescopes
f0
Objective
fe
f0
fe
Eyepiece
Reflector
Refractor
15
Color Vision

• Additive Color Theory
• Primary Colors
• Red
• Green
• Blue
• Secondary Colors
• Yellow
• Cyan
• Magenta