If Vega is apparent magnitude zero, and Deneb first magnitude, then
A) Deneb must be a main sequence star, and Vega a giant.
B) Vega must be 2.5× hotter than Deneb.
C) Deneb is one magnitude brighter than Vega.
D) Vega is about 100× brighter than Deneb.
E) Vega is 2.5× brighter than Deneb.
E
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On a planet whose Moon is in the same orbital plane as the planet's orbit around itsstar, how often will solar eclipses occur?
a) Twice every orbit of its moon (twice a month). b) Once every orbit of the planet around its Sun (its year). c) Twice every rotation of the planet (twice a day). d) Once every orbit of its moon (its month). e) Once every rotation of the planet (its day).
The radioactivity due to Carbon-14 measured in a piece of a wooden casket from an ancient burial site was found to produce 20.0 counts per minute from a given sample,
whereas the same amount of carbon from a piece of living wood produced 160. counts per minute. The half-life of Carbon-14, a beta emitter, is 5730. years. Thus we would estimate the age of the artifact to be about A) 14,800 years B) 20,000 years C) 5,700 years D) 17,200 years E) 11,500 years
Two toy cars (16 kg and 2 kg) are released simultaneously on an inclined plane that makes an angle of 30° with the horizontal. Which statement best describes their acceleration after being released?
A) The 16-kg car accelerates 8 times faster than the 2-kg car. B) The 2-kg car accelerates 8 times faster than the 16-kg car. C) Both cars accelerate at a rate of 8?g. D) Both cars accelerate at a rate of 0.866 g. E) Both cars accelerate at a rate of g sin(30°).
What is one of the differences between Cepheids and RR Lyrae variables?
A) The period-luminosity relation holds only for RR Lyrae stars. B) The pulsations of RR Lyrae stars are much less regular than those of Cepheids. C) Cepheids are giants, but RR Lyrae stars are still on the main sequence. D) All Cepheids have the same brightness, but RR Lyrae stars vary greatly in luminosity. E) The RR Lyrae stars have much shorter periods than Cepheids.