# Notes #3

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``` Frequency
 Wavelength
 Energy

Radio: Your radio captures radio waves emitted by
radio stations, bringing your favorite tunes. Radio
waves are also emitted by stars and gases in space.

Microwave: Microwave radiation will cook your
popcorn in just a few minutes, but is also used by
astronomers to learn about the structure of nearby
galaxies.

Infrared: Night vision goggles pick up the infrared
light emitted by our skin and objects with heat. In
space, infrared light helps us map the dust between
stars.

Visible: Our eyes detect visible light. Fireflies, light
bulbs, and stars all emit visible light.

Ultraviolet: Ultraviolet radiation is emitted by the
Sun and are the reason skin tans and burns. &quot;Hot&quot;
objects in space emit UV radiation as well.

X-ray: A dentist uses X-rays to image your teeth, and
airport security uses them to see through your bag.
Hot gases in the Universe also emit X-rays.

Gamma ray: Doctors use gamma-ray imaging to see
inside your body. The biggest gamma-ray generator of
all is the Universe.
ROYGB(I?)V
Review your units!
Wavelength (lambda):
Frequency (nu):
meters (m)
Hertz (Hz) or oscillations per second
 Faster than anything else on earth…
 Speed of light (c) = 3.00 x 108 meters per second (m/s)
 Use this number for your calculations.
 670,616,629 miles per hour
 186,282 miles per second
 983,571,056 feet per second
Wavelength and Frequency are INVERSELY PROPORTIONAL
 Calculate the wavelength of yellow light emitted by the
sodium lamp shown above if the frequency of
radiation is 5.10 x 1014 Hz (s-1).
 What is the frequency of radiation with a wavelength
of 5.00 x 10-8 m? In what region of the electromagnetic
spectrum is this radiation?
 h= planck’s constant= 6.626 x 10-34 joules&middot;second (J&middot;s)
 E = energy (joules) (J)
 v= frequency = oscillations per second (osc./s)
What is the energy of a photon of
microwave radiation with a frequency of
3.20 x 1011 s-1 (or Hz) ?
 When atoms absorb energy, electrons move into higher
energy levels. These electrons then lose energy by emitting
light when they return to lower energy levels.
This happens by passing an electric current through a gas.
2.0 x 10-7 m to 8.0 x 10-7 m.
They are giving you nanometers.
They just converted the numbers .
Each element has a unique emission spectrum. Like a fingerprint.
 Because each element has a unique emission
spectrum, we can determine the composition of the
universe…
 The atomic spectra of starts for example.
 They are hot glowing bodies of gases!
 Spectroscopist: finds the chemical contents of
unknown materials in chemical research.
 Chemical research
 Police Investigations: Forensics
 Studies of the Universe
 Environmental Scientist
 ETC.
 You decide…
 How much of THAT is in that?
 Unit 1 Test : Notes #1-3 and Article Materials
 Thursday August 28th
 Lab Report 1: Spectroscopy Inquiry
 We will begin process on September 2. Due date
to be announced.
```