1. Unit 8: Optics lesson 1: Electromagnetic radiation

2. What waves make up the electromagnetic spectrum?
10 min – point of emphasis: visible light is only a small portion!
(microwaves)

3. All waves in the electromagnetic spectrum travel at the speed of light.
= 3.0 x108 m/s
Example: Find the wavelength of each radio station.
“Rock-101” (101 MHz)
AM-600 (600 kHz)
10 min c f
3.0 x 108
a) c = f  so
 = = =
3.0 m
101 x 106 c f
3.0 x 108
b) c = f  so
 = = =
500 m
600 x 103

4. Brain Break!

5. What Causes Electromagnetic Radiation?
Changing magnetic fields cause electric fields (this is how generators work).
Changing electric fields cause magnetic fields (this is how electromagnets work).
Vibrating electrons cause changing electric fields which cause changing magnetic fields… e-
Vibrating
electron
10 min
Magnetic field electric field
Note: the wave of radiation travels in a straight line!

6. Law of reflection: өi = өr өi : angle of incidence
not shiny өi өr
normal line
(90)
10 min
өi : angle of incidence
өr : angle of reflection
shiny

7. Quick Review:
Pg. 210 #4 and 6
10 min

8. Unit 8: Optics lesson 2: images

9. Properties of an Image
Size: larger, smaller, or the same compared to looking directly at the object?
Location: where does the image appear to be compared to the object?
Type: real (the rays converge and the image can be projected onto a screen) or virtual (the rays do not converge and the image cannot be projected onto a screen)?
Attitude: upright or inverted (upside-down)?
15 min

10. Image in a Plane (flat) Mirror
10 min
Image Characteristics:
size –
location –
type –
attitude –
same
opposite (behind mirror)
virtual (the rays do not converge)
upright (laterally inverted)

11. Brain Break!

12. Pinhole camera ho hi do di Simplest and oldest type of camera. hi di
10 min hi ho di do
Image Characteristics:
size (hi) –
location –
type –
attitude –
smaller
M = =
closer
real (rays converge)
inverted
M = magnification

13. Try This:
A pinhole camera 300 mm long forms an image of a 180 cm tall man 4.5 m away. Find the size and other characteristics of the image.
hi/ho = di/do
hi = (di/do) x ho
= (30/450)x180
= 12 cm
10 min
location –
type –
attitude –
closer
real (rays converge)
inverted