The H-R diagram is a diagram plotting the stars according to their
A. luminosity and temperature.
B. spectral type and temperature.
C. mass and diameter.
D. brightness and luminosity class.
E. apparent brightness and temperature.
Answer: A
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Synchrotron radiation is produced by
a. objects with temperature below 10,000 K. b. high-velocity electrons moving through a magnetic field. c. cold hydrogen atoms in space. d. the collapsing cores of massive stars. e. helium flash.
Which of the following astronomical objects emit radiation mostly at non-visible wavelengths?
A. cold interstellar gas clouds B. dust clouds in space C. hot gas surrounding black holes D. All of these choices are correct.
What is the wavelength of a 0.40 kg object moving at 25 m/s?
A. 0.40 kg objects don't have wavelengths
B. 10 m
C. 0.10 m
D. 
E. 
When you pay the electric company by the kilowatt-hour, what are you actually paying for?
a) energy b) power c) current d) voltage e) none of the above