The first attempt to map the Galaxy via star counts was done by:
A) Galileo in 1612.
B) William Herschel in the late eighteenth century.
C) Edward Barnard with long exposure photos about 1900.
D) Harlow Shapley with the RR Lyrae variables in 1920.
E) Edwin Hubble with the new 100" Mt. Wilson telescope in the 1930s.
B
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Suppose that the energy difference between adjacent energy levels for an oscillator in an Einstein solid is ? = 0.005 eV. At room temperature, the value of T/TE is
A. quite a bit smaller than 1 B. about equal to 0.5. C. about equal to 1. D. about equal to 2. E. quite a bit larger than 2. F. One doesn’t have enough information to tell.
An infrared thermometer operates by way of
A) temperature differences. B) radiant energy invisible to humans. C) conduction, convection, and radiation. D) none of the above
Two very small +3.00-?C charges are at the ends of a meter stick. Find the electric potential (relative to infinity) at the center of the meter stick. (k = 1/4??0 = 8.99 × 109 N ? m2/C2 )
A) 0.00 V B) 2.70 × 104 V C) 5.40 × 104 V D) 1.08 × 105 V
The amount of radiation left over when all incoming and outgoing flows have been tallied is called __________.
What will be an ideal response?