1. Chapter 16.3 – Reflection and Color
every object reflects some light and absorbs some light
light ray –
a line in space that matches the direction of the flow of radiant energy
the direction of the light ray is the same as the direction light travels
geometrical optics –
study of light when light behaves like a ray
ray diagram –
diagram showing the path of light using light rays

2. Chapter 16.3 – Reflection and Color
diffuse reflection –
reflection of light in random directions by a rough surface
smooth surfaces reflect light in one direction
angle of incidence –
angle of the light rays hitting the surface
angle of reflection –
angle of the light rays reflecting off the surface

3. Chapter 16.3 – Reflection and Color
law of reflection –
the angle of incidence equals the angle of reflection
normal –
a line perpendicular to the point where light hits a surface

4. Chapter 16.3 – Reflection and Color
the colors we see depends on the frequencies and wavelengths of the light that reaches our eyes
recall v = λ ∙ f
a green object reflects green light and absorbs all other colors
black objects absorb all light
white objects reflect all light
If we shine red light on the football field what color will it appear to be?

5. Chapter 16.3 – Reflection and Color
additive primary colors –
red, green, blue
can be combined to produce all other colors
is how TV and computer screens produce color
subtractive primary colors –
yellow, cyan, magenta
- can be combined to create red, green, and blue

6. Chapter 16.3 – Reflection and Color
Mirrors
flat mirror –
the image appears the same size and distance from the mirror as you are, it seems the light is coming from behind the mirror
virtual image –
image from which light rays appear to diverge (spread out), even though they are not focused there
virtual images cannot be projected on a screen
virtual images seem to be behind the mirror

7. Chapter 16.3 – Reflection and Color
optical axis – a straight line though the center of the mirror focal point – the point where all light that travels parallel to the optical axis is reflected to meet at real image – image that is formed by the intersection of light rays - real images can be projected on a screen

8. Chapter 16.3 – Reflection and Color
convex mirror –
surface of the mirror is bulged out
the image is always virtual, upright, and smaller
it allows large areas to be viewed
they are the side mirrors on cars

9. Chapter 16.3 – Reflection and Color
concave mirror –
the surface of the mirror is curved inwards
if the object is far from the mirror, the object will be real and upside down
if the object is at the focal point, there is no image, the light does not converge to form an image
used in headlights and flashlights to form beams of light
if an object is between the focal point and the mirror, the image will be virtual, upright, and enlarged

10. Chapter 16.3 – Reflection and Color