Quiz 4 Astro 201 Fall 2010 Correct answer in bold letters 1 The main sequence for a star can best be described as the time when the star a is collapsing because of gravity b is fusing hydrogen into helium c is exploding d is fusing helium into carbon e is pulsating 2 Cepheid variable stars and RR Lyrae variable stars are of interest to cosmologists because a Their period of pulsation is correlated with their absolute magnitude b Their period of pulsation is correlated with their radial velocity c Their period of pulsation is chaotic d Their period of pulsation is independent of luminosity e Their period of pulsation is random 3 By plotting the HR diagram of a cluster of stars astronomers can figure out a The age of the cluster b The size of the cluster c The radial velocity of the cluster d The rotation of the cluster e The expansion of the cluster 4 An object which does not have enough mass to get hot enough for nuclear fusion to occur is called a A neutron star b A brown dwarf c A red giant d A black hole e A protostar 5 A white dwarf s gravitational contraction is prevented by a Thermal pressure b Electron degeneracy pressure c Neutron degeneracy pressure d Magnetic fields e Centrifugal force 6 In about years the Sun will stop being on the main sequence a 5000 years b 5 million years c 5 billion years d 50 billion years e 500 billion years 7 After the Sun is on the main sequence it will become a a Supernova b Planetary nebula c Protostar d Neutron star e Black hole 8 The carbon and oxygen we have on Earth was a Produced during the Big Bang b produced in the Sun c produced on the Moon d produced on Pluto e produced in stars that later blew up and enriched the gas from which the Sun formed 9 An example of conservation of angular momentum is a the speeding up of a skater s spin when she pulls in her arms b the fusion of hydrogen into helium c the pulsation of Cepheid variable stars d the explosion of a planetary nebula e the helium flash 10 A planetary nebula is a the expelled outer envelope of a medium mass star b produced by a supernova explosion c the gas cloud within which planets are forming d the disk which forms around a protostar e a cloud of hot gas lit up by hot massive O and B stars
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