• Question
9 (1 point) If a sunspot has a temperature of 4200 K and the solar surface has a temperature of 5800 K,
how many times
brighter is the surface compared with the sunspot? (Hint: Use the Stefan-Boltzmann law.)
a.It isn't brighter
-- it is fainter! b.About 1.4 times brighter. c.About 3.6 times brighter. d.About 5.6 times brighter.
•Sunspot
brightness, use E = σT4
• (T1/T2)4 = (5800/4200)4 = 3.6 times brighter
•
• Question
10 (1 point) Fusion of very light elements to make heavier ones releases energy, as does fission of very
heavy elements to make
lighter ones. The most "energetically favorable" and stable element from which neither fission nor fusion
can release energy
is
a.Hydrogen
b.Helium c.Carbon d.Iron
e.Uranium