PHYS 190 Study Guide - Final Guide: Astronomical Unit, Ecliptic, Supercluster
10 May 2018
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FB from FINAL:
1. The absolute magnitude scale is defined so that a difference of five magnitudes is a equivalent to a factor of ________ in
luminosity
- 100
2. A star at a distance of 100 pc has an apparent magnitude of 10. Its absolute magnitude is _________ (give a round
numerical answer, e.g. 10, not 10., or ten).
- 5
3. Two stars are observed to have the same apparent magnitude. One star has a parallax of 0.5" and the other has a parallax
of 1". Hence the more distant star is ___________ times more luminous than the closer one (give a round numerical answer,
e.g. 10, not 10., or ten).
-
4. Late in our Sun's life, it will fuse helium in its core to produce the nucleus of the element _______________. Enter the one-
word answer in lower-case letters, and use the correct spelling. (Note that I identified only one element in class, although
two elements are actually produced, either of which will be accepted as an answer).
- carbon
5. When the Sun becomes a red giant it will expel a ____________________ ______________ (two words), before collapsing
into its end state. Use the correct spelling, and all lower-case letters, for both words, no hyphens
- planetary nebula
6. Electron quantum ___________ pressure supports the crushing weight of a white dwarf star. Enter the one-word answer in
lower-case letters, and use the correct spelling.
- degeneracy
7. White _________ supernovae produce no neutron stars or black holes, only ejected debris. Enter the one-word answer in
lower-case letters, and use the correct spelling.
- dwarf
8. As its name implies, a ________ star has fused its protons and electrons. Enter the one-word answer in lower-case letters,
and use the correct spelling.
- neutron
9. A foreground super-cluster of galaxies can act as a __________________________ _________ (two words), due to its
enormous mass, producing a distorted image of a distant galaxy behind it. Use the correct spelling, and all lower-case
letters, for both words, no hyphens.
- gravitational lensing
10. The age of the universe is approximately _________ billion years. Write the answer in numerical form, and accurate to one
decimal place (as in 12.3, not 12, or twelve).
- 13.8
11. A core-collapse black hole may be indirectly detected from Xray radiation emitted by an ____________ disk, which is formed
by matter that is pulled inward by the black hole from a nearby companion star. Use the correct spelling, all lower case
letters.
- accretion
12. A pulsating variable star has a temperature that ranges from 4,000 to 8,000 Kelvins. When hottest, how much more energy
does each element of area of the star emit, compared to when it is coldest? Enter your answer as a round number (e.g. 2,
not 2. or two).
- 16
13. According to Hubble's Law, if galaxy A has 2X the recessional velocity of galaxy B, then galaxy A is moving how many
times faster than B? Enter the answer as a round number (e.g. 2, not 2. or two).
- 2
14. The ____________________ principle is that the universe is both isotropic and
homogeneous
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