1. EM Waves Textbook: 10.8 - 10.9, 9.6 Homework: Read pg 530 – 539
Do pg 533 # 1 – 4
pg 539 # 8, 10
pg 478 # 1 – 4
-The fourth dimension

2. Review:
A wave is a disturbance that travels through a medium carrying energy. They are described by:
Amplitude (A)
frequency (f)
period (T)
wavelength () [distance of one cycle]

3. Transmission of Light Index of refraction: , medium 1 is air
Snell’s law:
Transmission:

4. The Electromagnetic Spectrum

5. Properties of Electromagnetic Waves

6. 1) Electromagnetic waves are made up of __________________ oscillating electric and magnetic fields.
2) The electric and magnetic fields are _________________to each other.
3) The vibration of the electric and magnetic fields is perpendicular to the direction of the wave’s motion; therefore, electromagnetic waves are ______________waves.
4) The electric and magnetic fields vary sinusoidally in phase with each other; that is, they _____________the same sine-wave phase with respect to each other.
5) Electromagnetic waves travel at c (the speed of light) in a ________________. In other mediums, they travel at different speeds, which causes refraction.

7. Low Range Frequencies Extremely Low Frequency, ELF (3 - 30 Hz)
Super LF ( Hz)
Ultra LF (300 Hz - 3 kHz)
Very LF ( kHz)
Submarine Communications
Audible

8. Radio AM: 300 - 3000 kHz Shortwave/CB: 3 - 30 MHz FM/VHF: 30 - 300 MHz
Used for local communication
Bounces of ionosphere

9. Microwave UHF: 300 - 3000 MHz TV, Cells, Networking, Microwave Ovens
SHF: GHz
Networking, Radar, Satellite

10. Radio Astronomy
GHz
Molecular Hydrogen Produces 21 cm radiation
Trace star formation in our Galaxy

11. Infrared 750 nm - 1 mm You produce it (as heat)
Allows us to see through dust clouds in space to the centre of Galaxy

12. Visible
400 nm nm
ROYGBIV
Sun produces most of its light with a wavelength in the yellow - green

13. Ultraviolet
10 nm nm
Produced by the ionization of atoms

14. X Rays 0.01 - 10 nm High Energy Electrons
Penetrates tissue but not bone (too thick)
Produced by accretion disk of a black hole

15. Gamma() Rays < 0.01 nm Emitted from the nucleus
Emitted in nuclear reactions

16. Textbook: 9.1, 9.2 Homework: pg. 452 #3, 5, 6, 9
Waves in 2-D
Textbook: 9.1, 9.2
Homework: pg. 452 #3, 5, 6, 9
Applet: Circular Waves (Phet)

17. Properties of Waves
Transmission
Reflection

18. Diffraction

19. Properties of Waves Refraction
Total internal reflection: ONLY when waves travel from a more dense to a less dense medium

20. Pg 454
2. If waves with a wavelength of 2.0 m pass through an opening of 4.0 m in a breakwater barrier, will diffraction be noticeable?
3. Electromagnetic radiation with a wavelength of 6.3 x 10–4 m passes through a slit. Find the maximum slit width that will produce noticeable diffraction.

21. Light: Wave or Particle?
Wave (Christiaan Huygens)
Particle (Isaac Newton)
Rectilinear Propagation
Diffraction
Reflection
Refraction
Partial Reflection
Dispersion
Wave fronts travel in straight lines
Light travels very fast
Very small effect caused by collisions
If /w 1: increase proportionally
True if perfectly elastic collisions
A property of waves
Higher index  Lower speed
Higher index  Higher speed
A property of waves
Newton’s “Theory of fits”
True if violet = small ;
red = large 
True if violet = low mass;
red = high mass

22. Interference in 2-D & Young’s Double Slit Experiment
Textbook:
Homework: pg. 460 # 8, 9
pg. 475 # 3, 5 - 7, 9
READ 9.4

23. Review of Interference
When two waves meet their amplitudes add (like adding functions)
Constructive Interference: New amplitude is larger
Destructive Interference: New amplitude is smaller
Nodes are locations of complete destructive interference

25. Two Point Source Interference
A point Pn is on the nth nodal line created by two sources at S1 and S2 if:
If S1 and S2 are a distance d apart and Pn is far from the sources then:
Where n is measured from the right bisector of S1S2

26. Two Point Source Interference
Again, if Pn is far from S1 and S2
Where xn is the perpendicular distance from the right bisector of S1S2 and L distance from Pn to the midpoint of S1S2
Pg. 459 #2

27. Pg 459 # 9
An interference pattern is set up by two point sources of the same frequency, vibrating in phase. A point on the second nodal line is 25.0 cm from one source, 29.5 cm from the other. The speed of the waves is 7.5 cm/s. Calculate the wavelength and the frequency of the sources.
3.0 cm; 2.5 Hz
3.0 cm; 2.5 Hz

28. YDSE xn d n L Monochromatic light source
Discuss physical set up. And issues in Young’s time
- How small do the slits need to be?
- How close should the slits be to see interference?
- How do we produce a monochromatic source?

29. YDSE Destructive interference: Constructive interference:
Distance between nodal lines:
Discuss “Poisson’s Bright Spot”

30. Pg. 273 # 1
A student performing Young’s experiment with a single-colour source finds the distance between the first and the seventh nodal lines to be 6.0 cm. The screen is located 3.0 m from the two slits. The slit separation is 2.2 x 10-2 mm. Calculate the wavelength of the light.
x 10-8 m
7.3 x 10-8 m

31. Pg. 273 # 2
Single-colour light falling on two slits mm apart produces the fifth-order fringe at a 3.8° angle. Calculate the wavelength of the light.
x 102 nm
6.2 x 102 nm

32. Pg 273 # 8
In an interference experiment, reddish light of wavelength 6.0 x 10-7 m passes through a double slit, hitting a screen 1.5 m away. The distance between the first and eleventh dark bands is 2.0 cm.
(a) Calculate the separation of the slits.
(b) Calculate the spacing between adjacent nodal lines using blue light (λblue = 4.5 x 10-7 m).
8. (a) 1.5 x 10-3 m (b) 4.5 x 10-4 m
(a) 4.5 x 10-4 m (b) 1.5 x 10-3 m