Which of the following properties of stars is directly observed (i.e., it can be measured by a calibrated instrument on a telescope, from a single observation without a need for additional calculations)?
A) luminosity
B) radius
C) surface temperature
D) apparent brightness
D) apparent brightness
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Consider a system consisting of two Einstein solids P and Q in thermal contact. Assume that we know the number of atoms in each solid and ?. What do we know about the system if we also know the total energy of the combined system?
A. Its macrostate B. Its microstate C. Its macropartition D. Its microstate and macropartition E. Its macrostate and macropartition F. Its macrostate and microstate T. Its macrostate, microstate, and macropartition
What kind of galaxy is the 'Milky Way?'
A: Spiral. B: Elliptical. C: Compound. D: Dwarf. E: Irregular.
The intensity of radiation reaching the Earth from the Sun is 1350 W/m2. The Earth's radius is 6.4 × 106 m. How big a force does this radiation exert on the Earth? (Assume it is all absorbed.)
A. 5.8 × 108 N B. 1.2 × 109 N C. 2.3 × 109 N D. 4.6 × 109 N E. 1.7 × 1017 N
According to the Arrhenius theory, basic properties are caused by ______________ ions
Fill in the blank(s) with correct word