Use these questions to test your understanding. If you get them wrong, you will be linked back to the relevant part of the notes. 

Be sure you study them thoroughly (don't just get a quick fix for your mistake) so your overall understanding is improved.

1. The current status of a star is determined by its

     a. age, mass, initial composition             b. temperature, distance, color

     c. spectral type, composition, temperature              d. distance, magnitude, color

     e. age, color, spectral type

2. A star will become a red giant when

     a. it begins to convert H to He         b. when its composition changes

     c. when it can no longer convert H to He in its core          d. when it gains mass

     e. none of the above

3. A star may be a variable star because

     a. it alternately expands and contracts             b. planets fall into it and block the light

     c. it makes more or less dust              d. its mass changes

     e. stars don't vary

4. The oldest stars are most likely to be

     a. the brightest stars         b. the most massive stars        c. the hottest stars

     d. the least massive stars         e. the stars with largest percentage of hydrogen

5. The lower limit on the size of a star is set by

     a. the size of cloud fragment that can form              b. the gravitational field of a cloud

     c. the amount of H that can coalesce             d. the mass require to get the core hot enough for conversion of H to He

     e. there is no lower limit

     a. temperature         b. color        c. radius         d. composition         e. distance

     e. there is no upper limit

Here are the properties of three main sequence stars: 1.)Barnard's Star T= 3370° K L=0.005 L_Sun   ; 2.) Sun T= 5800° K L = 1 L_Sun

3.) Spica T=26,000° K L = 23,000 L_Sun

8. List these stars in order of increasing mass.   

     a. Spica, Sun, Barnard's Star        

     b. Spica, Barnard's Star, Sun        

     c. Barnard's Star, Sun, Spica    

     d. Barnard Star's, Spica, Sun       

     e. Sun, Barnard's Star, Spica

9. Under what circumstances can a star convert oxygen to silicon?

     a. when it makes dust in its outer layers

     b. when it reaches the main sequence

     c. when it becomes a white dwarf

     d. when it becomes a black hole

     e. when the core of a massive star gets hot enough