1. Do Interactive exercise #2 that is located in Module 2 Lecture D. This exercise refers to identifying elements AX and BX. You may use the measurement widget but do not "publish to global view". Just use that to record the wavelengths which you can then later put in your email document. To the right is an example screen shot for element AX showing the 4 spectral lines (wavelengths omitted) that you would need to match up with the periodic table of elements. The white line at the top labelled 4105/0 is what you slide up up and down to measure the wavelengths of the 4 dark lines. Your response to this question should include
   • the wavelengths of the identified lines in AX and BX.
   • Which element in the periodic table that you think corresponds to AX and BX (remember, AX and BX both are elements with atomic numbers less than 20)

   
   
   
   
   
   
   
   

2. For main sequence stars, there is a relationship between their total mass and their energy output (which we call the luminosity). Report on the form of this relationship and how it was empirically discovered.

3. Astronomers have recently discovered a new spectral type for stars. They are classified as Spectral type L. When were these stars first discovered, how were they discovered and what kind of stars do they appear to be?
   
   

   These 4 questions are designed to test your knowledge of applying the inverse square law. All units are in relative units.

   The following shows the properties of 5 stars. Luminosity refers to the intrinsic energy output of the star and all luminosity values refer to the luminosity of Star A which is 1 luminosity Unit.

   Star A is at a distance of 10 distance units and deposits a flux of 100 flux units on our detector.

   Believe it or not, this is all the information needed to answer the questions. All of the units are relative to Star A so you simply scale from what you know for Star A to determine either the flux, luminosity or distance of the other Stars.

   • Star A: Luminosity = 1 luminosity unit Distance = 10 distance units Flux = 100 flux units
   • Star B: Luminosity = 1 luminosity unit Distance = 100 distance units
   • Star C: Luminosity = 4 luminosity units Distance = 40 distance units
   • Star D: Flux = 200 flux units Distance = 10 distance units
   • Star E: Luminosity = 1 luminosity unit Flux = 25 flux units

   Show all work or reasoning in answering the following questions.

4. What is the number flux units on the detector for Star B?

5. What is the number of flux units on the detector for Star C?

6. What is the number of luminosity units of star D?

7. What is the distance of Star E?