Understanding the Pakistan Budgeting Process: Basics and Key Insights
03 light and mirrors
1.
2. Light travels in straight lines…
We can illustrate this by using “light rays”
Light rays:
Using light rays to determine how light behaves is
called “geometric optics”
3. 3 types of matter that light encounters…
Transparent
Translucent
Opaque
8. LAWS OF REFLECTION
1)The angle of incidence
equals the angle of
reflection
∠i = ∠r
2)The incident ray, the
reflected ray, and the
normal all lie in the
same plane
Angle of
incidence
Angle of
reflection
12. Reflecting Light off Surfaces
1)SPECULAR REFLECTION
Reflection off a smooth
surface
2) DIFFUSE REFLECTION
Reflection off an
irregular/dull surface
13. Reflection and Dyslexia
- Too much glare off
white paper (too much
reflected light).
- Contrast between black
text and white paper is
too high.
- Use colour
filters/glasses to reduce
glare
15. Using light rays to see an object
Virtual image: An image in which light does not actually
arrive at or come from the image location
Virtual image
16. Step 1
Identify the top and the bottom of the object
(label these “A” and “B”)
17. Step 2
• Draw a line from point A that is
perpendicular to the mirror
18. Step 3
• Draw an incident ray
(starting at point A)
• Draw a “normal” where
the incident ray hits the
mirror
• Use a protractor to draw
a reflecting ray
(Remember that ∠i = ∠r )
19. Step 4
• Extend line A to point Ai (equidistant from
point A on the other side of the mirror)
• Connect point Ai to your reflection ray
