the wave nature of light section 6.1. objectives study light (radiant energy or electromagnetic...
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The Wave Nature of
Light
Section 6.1
ObjectivesStudy light (radiant energy or electromagnetic radiation) as having wavelike properties.
Identify the characteristics of wavelength, frequency, and speed
Key TermsElectromagnetic radiation
Wavelength
Frequency
Speed
Why Study Light?Our understanding of the electronic structure of atoms came from the analysis of light either emitted or absorbed
Visible Light
Light we can see with our eyes
An example of electromagnetic radiation
Electromagnetic Radiation
Carries energy through spacea.k.a radiant energy
Many types of ERVisible lightRadio wavesInfrared radiationX rays
The different forms of ER share certain fundamental characteristics
They all move through a vacuum as the speed of light:
3.00 x 108 m/s
Radio AND X rays??
Wavelike Characteristics
All ER types also behave like water waves
Up and down motion
Pattern of peaks and troughs repeated at regular intervals
Wavelength, Shortest distance between equivalent points on a continuous wave
Between 2 adjacent peaks or troughs
Measure in meters or nm
Frequency, Number of complete wavelengths or cycles that pass a given point per second.
Measured in Hz (Hertz)
AmplitudeWave’s height from the origin to a peak, or from the origin to a trough
Relates to the intensity of the radiation
Characteristics of Waves
What makes water waves travel at various speeds?
ER versus Water Waves
ER move at the same speed
Wavelength and frequency are always related
c
c
c
Why Your Radio Won’t Take an X rayER types have different properties as a result of their varying wavelengths, expressed in units of length
Electromagnetic Spectrum
A VERY Large Spectrum
Gamma rays =
Radio waves =
Don’t Forget…
ROY G BIV
Order of colors (LS) on the visible spectrum
Practice Problem• The yellow light given off by a sodium
vapor lamp used for public lighting has a wavelength of 589 nm. What is the frequency of this radiation?
Solution
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