Why do hydrogen gas clouds glow red?
A: Remnants of ancient supernova explosions, they've cooled from white hot to reddish over the course of millions of years.
B: Their light is highly red-shifted because of the high speeds with which the gas clouds are moving.
C: They're members of the Cool Cosmic Clouds Party (CCCP).
D: Decay of trace radioactive elements within them heats the clouds until they glow red.
E: Electromagnetic radiation from nearby stars heats the clouds until they glow red.
Ans: E: Electromagnetic radiation from nearby stars heats the clouds until they glow red.
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A fusion reaction releases energy because the binding energy of the resulting nucleus
A) is less than the binding energy of the original nuclei. B) is absorbed in the process. C) is equal to the binding energy of the original nuclei. D) is greater than the binding energy of the original nuclei. E) is released in the process.
Which of the following will not influence the rate at which nuclear reactions will occur in a nuclear power plant where the fuel elements are a mixture of 235U and 238U?
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Legend says that Archimedes, in determining whether or not the king's crown was made of pure gold, measured its volume by the water displacement method. If the density of gold is 19.3 g/cm3, and the crown's mass is 440 g, what volume would be necessary to prove that it is pure gold?
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