Wednesday 10-1-14
• WU: Compare a radio wave to a microwave.
a) Which has a higher frequency? Microwave
b) Which has a longer wavelength? Radio Waves
• Check Starlight Starbright worksheet
• Spectrum Analysis
To Do
 Quizlet has been moved to Friday
 Grade Star Light, Star Bright
 Update SN
 Spectrum Analysis
HW: Universe CBA Review
All missing assignments must be turned in by Thursday – no exceptions!
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Color in the above spectrum on your sheet
What color has the largest wavelength? Red
Smallest wavelength? Violet
What color has the highest frequency? Violet
Lowest frequency? Red
What color would you expect to see if its wavelength
were:
– 600 nanometers? Orange
– 450 nanometers? Blue
– 650 nanometers? Red
• Skip to part 3 (we’ll come back to part 2)
Below are the bright line spectra of four elements and the
spectrum of an unknown gas.
700
a) Which elements are in the unknown? Explain.
Hydrogen and Helium. The unknown has all of the hydrogen and helium lines.
b) Why are you able to exclude the presence of the other
elements?
The unknown does not contain all of the lines for lithium or sodium
c) Young stars are mostly hydrogen with a small abundance of
helium and other elements. Is the unknown a likely
spectrum for a young star? Explain your answer.
Yes this is likely to be a young star because it contains hydrogen and helium
400
-Spectrums A, B, and C are from identical stars.
-A represents a spectrum from an unmoving star.
-B and C show stars in motion with respect to us
1.
2.
3.
4.
What is the approximate range in nanometers that the black lines fall in for each
spectrum. A = 550-570
B= 600-650
C= 430-470
C – Blue shifted
Which spectrum is that of a star moving toward Earth? Explain.
(smaller
B
–
Red
shifted
Moving away from Earth?
wavelength)
(longer wavelength)
In comparison to A, which is moving faster. B or C? Justify your answer.
C, it is shifted farther from original