Download Stellar Evolution Test Answers

Stellar Evolution Test
Name_________________________________
Date_________________
1. When the light from a distant galaxy is distorted by a black hole, the resulting image is a ring. We call
this a) the photon sphere b) the event horizon c) gravitational lensing d) the cosmological principle
2. Once you cross the ____________________, there is no going back…light can no longer escape.
a) photon sphere b) event horizon c) singularity d) cosmological boundary
3. When we are able to observe a neutron star’s electromagnetic radiation bursts from Earth, we called
the neutron star a a) burster b) quasar c) pulsar d) planetary nebula
4. When hydrogen burning starts on a neutron star, it does so explosively, and a ____________ results.
a) burster b) quasar c) pulsar d) planetary nebula
5. . Einstein’s general theory of relativity describes gravity in terms of the warping of space-time by the
presence of a) mass b) a pulsar c) a black hole d) a neutron star
6. The boundary at which escape speed from a collapsing star equals the speed of light is called the
a) photon sphere b) Schwarzchild radius c) singularity d) cosmological boundary
7. A clock would appear to _________as a spacecraft approached the event horizon of a black hole.
a) slow b) not be affected c) speed up
8. To a distant observer, light leaving a spaceship that is falling into a black hole would be subject to
a) a gravitational blue shift b) no significant change in color c) a gravitational red shift
9. The best way to look for a black hole is in a binary star system in which one component is a compact
a) white dwarf b) neutron star c) red giant d) x-ray source
10. Once within the event horizon, no known force can prevent a collapsing star from contracting all the
way to a____________, at which point the density and the gravitational field of the star become infinite.
a) neutron star b) singularity c) white dwarf d) black dwarf
11. Type Ia supernovae come from exploding
a) neutron stars b) high-mass stars c) white dwarfs d) black dwarfs
12. Type II supernovae signal the dramatic death of
a) neutron stars b) black holes c) high-mass stars d) low-mass stars
13. The fusion of iron into heavier elements requires energy but does not liberate energy.
a) true b) false
14. Gravity defeats electron degeneracy pressure by forcing a) protons and neutrons to form electrons
b) protons and electrons to form neutrons c) neutrons and electrons to form protons
15. Electron degeneracy pressure halts the collapse of the core of a star on its way to becoming a
a) neutrons star b) black hole c) planetary nebula d) red giant
16. A spinning neutron star emitting light is called a
a) quasar b) burster c) planetary nebula d) pulsar
17. Supermassive stars may very well have been the first stars formed in our universe. A) true b) false
18. What element is the key component of stars? a) hydrogen b) helium c) carbon d) oxygen
19. A cloud of gas and dust ________times the diameter of our solar system is needed to produce a star
the size of our sun. a) 10 b) 100 c) 1000 d) 10000
20. When the central material in our huge rotating cloud of gas and dust comes together and reaches
about _________million degrees, a protostar is formed. a) 200 b) 100 c) 20 d) 2
21. The most common type star in the universe is the
a) brown dwarf b) white dwarf c) yellow dwarf d) red dwarf
22. A star hotter than the sun would tend to be more _________in color.
a) yellow b) red c) blue
23. That which drives the life history of a star is its mass. a) true b) false
24. More massive stars live _____________ less massive stars.
a) longer than b) about the same amount of time as c) shorter than
25. When the outward pressure of fusion balances the inward force of gravity, the star is in equilibrium.
We can say the star has become a a) main sequence star b) protostar c) neutron star d) white dwarf
26. The most important force in astronomy is
a) the nuclear force b) the electromagnetic force c) gravity d) mass
27. Most stars are not part of binary or multiple star systems. They live out their lives like our Sun,
without a companion star. a) true b) false
28. The ejected gas illuminated by the remaining hot central core from a low-mass star
a) white dwarf b) planetary nebula c) supernova d) burster
29. In a low-mass star, with most of the helium burned and shell hydrogen burning continuing, outer
layers expand greatly, cool, redden and form a
a) yellow giant b) red giant c) yellow supergiant d) red supergiant
30. A high-mass star on the main sequence is _______________than our star.
a) hotter b) bluer c) more luminous d) all of these
31. The remnant of a supernova will go on to form
a) a neutron star b) a black hole c) either a or b d) both a and b
32. When hydrogen is no longer fusing helium, the core shrinks and becomes hotter. At a core
temperature of about 100 million K, helium fuses to carbon
a) Type 1a supernova b) Type II supernova c) helium flash d) planetary nebula