How did astronomers discover the relationship between spectral type and mass for main sequence stars?
a. by measuring stellar radii with very powerful optical telescopes
b. by measuring stellar radii with very powerful radio telescopes
c. by comparing stars with the same spectral type but different luminosities
d. by using computer models of hydrogen fusion and stellar structure
e. by measuring the masses and spectral types of main-sequence stars in binary systems
e
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Two equal mass objects (which are in thermal contact) make up a system that is thermally isolated from its surroundings. One object has an initial temperature of 100°C and the other has an initial temperature of 0°C
What is the equilibrium temperature of the system, assuming that no phase changes take place for either object? (The hot object has a specific heat capacity that is three times that of the cold object.) A) 23°C B) 19°C C) 75°C D) 50°C E) 25°C
The intensity level of a power mower at a distance of 1.0 m is 100 dB. You wake up one morning to find that four of your neighbors are mowing their lawn 20 m from your open bedroom window. What is the intensity level in your bedroom?
A) 80 dB B) 104 dB C) 400 dB D) 50 dB E) 40 dB
The elastic modulus of a material, except for elastomers, is proportional to the _____________of the interatomic potential.
Fill in the blank(s) with the appropriate word(s).
Two oppositely charged particles ______________ one another
Fill in the blank(s) with correct word