1. Catalyst 11/29/12 Draw the Bohr model of a Chromium atom.
How many protons does the most common isotope of uranium have? How many neutrons?

2. Agenda 11/29/12 Catalyst Announcements
Purchase spiral notebook ASAP!
HW: Create a QuickStudy sheet for Packet#3 Material DUE MONDAY, 12/3/12
Introduction to the Properties of Light
Class Practice
Exit Slip

3. Class Points
Your class can earn class points if:
everyone in class:
Comes to class quietly and on time
Stays focused and on task during class
Leaves classroom neat and organized
Students are teaching other students
Majority of class participates
Follows all classroom expectations and procedures
And more…
P3: 18 pts (on time and focused) P4: 17 pts ( on time and focused) P6: 18 pts (on time and focused)

4. Take out your notebooks!
If you don’t have one, take notes on your iPad or on a separate piece of paper. You will eventually need to transfer it to a notebook so get one ASAP.
During these types of lessons: DO NOT COPY DOWN EVERYTHING. Only important points and formulas!
Highly recommend CORNELL STYLE

5. Objective
We will be able to explain the mathematical relationship among the speed, wavelength and frequency of electromagnetic radiation.

6. INSERT VIDEO – ELECTROMAGNETIC SPECTRUM INTRO

7. Defining a Wave Wavelength - distance from CREST to CREST
Frequency - cycles per second; how many peaks pass a given point in 1 second

8. distance between any two peaks/crests on a wave
WAVELENGTH l
distance between any two peaks/crests on a wave
Units = m

9. What are the units on wavelength
What is Measured
Unit(s)
Symbol(s)
Wavelength m λ

10. cycles per second; how many peaks pass a given point in 1 second
FREQUENCY f
cycles per second; how many peaks pass a given point in 1 second
Units = 1/s or Hz

11. What are the units on frequency
What is Measured
Unit(s)
Symbol(s)
Frequency
1/s or Hz f

12. Velocity = wavelength multiplied by frequency
v = l x f
Velocity = wavelength multiplied by frequency
Units = m/s

13. Understanding Waves • Example: Light • Snake
• Transverse Waves - displacement is perpendicular to
the direction of motion of the wave
• Example: Light
• Snake

14. Light is an Electromagnetic Wave

15. Special Things About a Light Wave
• It does not need a medium through which to travel
• It travels with its highest velocity in a vacuum
• Its highest velocity is the speed of light, c,
equal to 300,000 km/sec
• The frequency (or wavelength) of the wave determines
whether we call it radio, infrared, visible, ultraviolet,
X-ray or gamma-ray.

16. Frequency vs. Wavelength

17. EM Radiation Travels as a Wave
c = 3 x 108 m/s
It’s not just a good idea, it’s the law!

18. EM Spectrum Probes the Universe

20. Frequency and Wavelength Calculations
The wavelength of the green light from a traffic signal is centered at 522 nanometers. (1 nanometer = 1 x 10-9 meter). What is the frequency of this radiation?

21. You Try!
Your cellphone emits a radiowave with a frequency of 2100 MHz. Calculate the wavelength of this microwave. (1 Megahertz = 1 x 106 Hertz).

22. Fun problem!
A cell phone tower in Elizabeth emits an electromagnetic wave with a frequency of 2100 MHz. Will this wave reach Overlook Hospital in Summit, NJ? (1 Megahertz = 1 x 106 Hertz).

23. Exit Slip (Quietly and Independently)
Complete on Notability and this to me by the end of the period.
Light is considered to be a __________________ wave.
What is the relationship between wavelength and frequency?
Calculate the frequency of a wave with a wavelength of 900 nm. (1 nm = 10-6 m). Show all your work.