SMT 314 - Introduction to Cosmology » Fall 2020 » Exam 3

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Question #1
Which statement regarding deuterium is false?
A.   It has one neutron and one proton.
B.   It is an isotope of hydrogen.
C.   It has one electron, so it is not an ion.
D.   It has one more proton than an average hydrogen atom.
Question #2
Spherical aberration is a problem in ________________ telescopes and refers to __________________.
A.   reflecting; differing focal points from different parts of the mirror.
B.   refracting; the smearing of light due to atmospheric turbulence.
C.   space; the deformation of the glass due to the absence of gravity.
D.   refracting; different focal lengths for different wavelengths of light.
E.   reflecting; the smearing of light due to atmospheric turbulence.
Question #3
What parameters must be equal to obtain hydrostatic equilibrium? (Choose all correct answers),,
A.   pressure
B.   gravity
C.   temperature
D.   mass
Question #4
Which statement is false:
A.   sunspots and heliosiesmology are associated with the photosphere
B.   a photo of the Sun with a x-ray filter will show the chromoshere
C.   the corona is the solar wind
D.   the chromosphere is best viewed with a H-alpha filter
Question #5
Only fully formed stars are found on the main-sequence. Protosuns are not.
A.   TRUE
B.   FALSE
Question #6
At mid-northern latitudes (California), the full moon passes higher in the sky in winter than in summer.
A.   FALSE
B.   TRUE
Question #7
Ages of open star clusters can be determined by the length of their Main Sequence stars. If an open cluster has a few blue stars and many white, yellow & red dwarfs, what is the age?
A.   young (< millions of years)
B.   > 10 billion years
C.   5 billion years
Question #8
Continuous radiation (a stellar spectrum) from the photosphere of a star is called a blackbody curve. If a star has a surface temperature four times higher than that of our Sun, what is the most-likely color of the star?
A.   white
B.   green
C.   blue
D.   red
Question #9
To calculate the distance a star is from us, we measure the apparent magnitude and compare it to the absolute magnitude of the star. We know that the intensity, I, diminishes with increased distance, D, (I is inversely proportional to D2). Identify an object for which we know the absolute magnitude.
A.   long period variables
B.   brown giants
C.   binary stars
D.   Cepheids
Question #10
Massive stars live significantly longer lives than low-mass stars, since they have much more fuel available to them
A.   FALSE
B.   TRUE
Question #11
Every star emits "black body" radiation described by Wein's Law: At the peak radiation, the wavelength is inversely proportional to:
A.   core temperature
B.   photosphere temperature
C.   speed of light
D.   emitted intensity
E.   fusion density
Question #12
What subatomic particles are found in an atomic nucleus? Mark all the correct answers.,,
A.   protons
B.   Bohr model
C.   electrons
D.   valence shields
E.   neutrons
Question #13
Which one of the following statements about the birth of stars is false?
A.   Contracting balls of gas with masses below about 75 Jupiter masses actually end up as brown dwarfs, not main-sequence stars.
B.   Gravitational contraction of a pre-main-sequence star ceases once nuclear reaction begin.
C.   Stars form from gaint clouds of gas and dust whose collapse and fragmentation (clumping) are due to gravity.
D.   During gravitational contraction, the temperature in the core of a pre-main-sequence star decreases.
Question #14
How many neutrons are in the nucleus of isotope ? Oxygen 18 is used to determine how much of the world's oceans were frozen during past ice ages.
A.   10
B.   18
C.   8
D.   7
Question #15
Inverse square law: If Stars Fred and Ernie have the same apparent brightness, but Star Fred is 4 times farther away from Earth than Star Ernie, then Star Ernie's luminosity (absolute magnitude) is _________ times the luminosity of Star Fred. o Earth * Ernie * Fred
A.   4
B.   1/4
C.   16
D.   1/16
Question #16
When we see other people, our eyes are detecting the visible light that each of us radiates as an approximate "blackbody" (thermal emitter).
A.   FALSE
B.   TRUE
Question #17
The star Sirius has a brighter apparent magnitude than its absolute magnitude. Which statement is correct?
A.   Sirius is located less than 10 ps from Earth.
B.   Sirius is located 10 ps from Earth.
C.   This is an impossible situation. The apparent magnitude can't be more than the absolute magnitude.
D.   Sirius is located greater then 10 ps from Earth.
Question #18
Jovian planets have rings because
A.   Jovian planets rotate very rapidly, and some material near the equator of these planets was flung outward, forming the rings
B.   their thick gaseous atmospheres would disintegrate any small rock that enter them
C.   there is too much material to have fit into the ball of each planet
D.   tidal forces cause volcanic eruptions on some moons, and part of this material subsequently escaped the gravity of the moons, forming the rings.
E.   tidal forces prevent the material in rings from forming into moons
Question #19
The luminosity of a massive main-sequence stars are greater than those of low-mass main-sequence stars.
A.   TRUE
B.   FALSE
Question #20
Which planet's orbit is elliptical enough that the seasons are not equal in length?
A.   Venus
B.   Earth
C.   Mars
D.   Uranus
Question #21
If the spectrum of Star Amy peaks at optical wavelengths, and Star Johnny's surface is twice as hot as Amy's surface, then Johnny's spectrum peaks in the ultraviolet.
A.   TRUE
B.   FALSE
Question #22
Which statement is false:
A.   Hydrogen normally has one neutron.
B.   Normal hydrogen is also called protium.
C.   Hydrogen normally has one electron.
D.   Hydrogen normally has one proton.
Question #23
The resolution (clarity) of images obtained with large ground-based optical telescopes is generally degraded by turbulence in Earth's atmosphere, unless special correction techniques are used.
A.   TRUE
B.   FALSE
Question #24
If the spectral lines are shifted in color toward longer wavelengths, we can derive the speed of an astronomical object:
A.   not speed, but energies due to temperature
B.   across the field of view
C.   toward us
D.   away from us
Question #25
Which kind of star clusters have a few hundred stars and are located primarily in the galactic disk?
A.   elliptical galaxies
B.   open clusters
C.   megaclusters
D.   Mira clusters
E.   globular clusters
Question #26
During times of sunspot maximum, an unusually large number of prominences, solar flares, and coronal mass ejections also occur on the Sun.
A.   TRUE
B.   FALSE
Question #27
Which one the the following statements about atoms is false?
A.   Photon emission occurs randomly, in any direction.
B.   An electron in an atom may absorb either part or all of the energy of a photon.
C.   Each element produces a unique pattern of spectral lines, like a fingerprint.
D.   Absorption occurs when an electron in an atom jumps from a lower energy level to a higher energy level.
E.   Electrons have discrete energy levels.
Question #28
The type of spectral feature, usually observed from a hot gas without a star behind it, is an absorbtion line.
A.   TRUE
B.   FALSE
Question #29
The oscillating brightness light curves of RR Lyrae and Cepheid Variable stars identify known absolute magnitudes for these stars; so we can compare absolute and apparent magnitudes to estimate a star's ________.
A.   distance
B.   core temperature
C.   mass
D.   expansion/contraction
Question #30
When an atomic electron drops from a higher energy state to a lower energy state, it emits
A.   an ion
B.   an electron
C.   a neutron
D.   a photon
E.   a proton
Question #31
Thoroughly studying certain types of binary stars in the main way in which astronomers directly measure stellar masses.
A.   TRUE
B.   FALSE
Question #32
The 11-year sunspot cycle is driven by:
A.   a constant dipole magnetic field
B.   granulation oscillations
C.   differential rotation, winding up the magnetic fields
D.   nuclear explosions
E.   the Zeeman effect and the Maunder minimum
Question #33
Which celestial body has a retrograde rotation?
A.   Triton
B.   Venus
C.   Io
D.   Uranus
Question #34
Which fusion process occurs in our Sun?
A.   triple alpha process
B.   carbon-nitrogen-oxygen cycle
C.   proton-proton chain
D.   nucleosynthesis
Question #35
Isotopes are atoms:
A.   with extra protons
B.   with extra neutrons
C.   with extra electrons
D.   with extra neutrinos
Question #36
Protostars are born when:
A.   A large gas ball spins out of a larger star when disrupted by a passing star.
B.   Dark clouds hide large gas balls that are ignited by passing stars.
C.   An explosion throws out mass that settles as a star.
D.   Gravity causes a cloud of gas & dust to collapse toward a center.
Question #37
Brown dwarfs are formed by the same initial process that forms main-sequence stars, but they are less massive.
A.   FALSE
B.   TRUE
Question #38
An astrometric binary pair is identified by:
A.   varying star intensities
B.   converging spectral lines
C.   2 visible stars orbiting each other
D.   oscillatory (wobbly) star motions
Question #39
The Sun doesn't have a perfect blackbody spectrum because
A.   the Sun is too hot to radiate at all wavelengths.
B.   its core is much hotter than its surface, so the shape of the curve is distored.
C.   the coronal mass ejections interfere with the photons, adding too much noise to the spectrum.
D.   the relatively cool outer layers absorb photons emitted in the hot inner parts of the Sun, producing absorption lines.
E.   its spectrum consists of emission lines of the elements in the Sun, so there are some gaps.
Question #40
In some cases, radio telescopes at many different locations have been used together, combining the light, to produce images with much higher resolution than that of the individual telescopes
A.   TRUE
B.   FALSE
Question #41
Suppose exoplanets Luke and Leia both orbit the same star. The orbital period of exoplanet Luke is five times longer than that of exoplanet Leia. Compared with exoplanet Luke, exoplanet Leia is _________ to its star.
A.   now way to tell with available data
B.   farther
C.   the same distance
D.   closer
Question #42
The retrograde motion of Pluto can be attributed to the relatively high eccentricity of its orbit around the Sun, as compared normal planets.
A.   FALSE
B.   TRUE
Question #43
Per photon, ultraviolet photons have more energy than radio photons
A.   FALSE
B.   TRUE
Question #44
A binary star that varies in apparent brightness as one member of the binary passes in front of the other is
A.   a spectroscopic binary
B.   an astrometric binary
C.   an eclipsing binary
D.   impossible, unless at least one of the two stars if itself intrinsically variable.
E.   a visual binary
Question #45
The solar activity cycle has a period of about 11 years, including the magnetic pole reversal.
A.   FALSE
B.   TRUE
Question #46
  
A.   have more mass than lower-energy photons.
B.   travel less distance between their source and the observer than lower-energy photons.
C.   are not as likely to become redshifted as lower-energy photons.
D.   move faster than lower-energy photons.
E.   have higher frequencies and shorter wavelengths than lower-energy photons.
Question #47
Stars generate their energy through nuclear fission, the breaking apart of unstable, heavy elements into lighter ones.
A.   FALSE
B.   TRUE
Question #48
Which pair of scientific notation match 0.004 5 32,000
A.   45 x 10-4 3.2 x 104
B.   4.5 x 103 32 x 103
C.   4.5 x 10-3 3.2 x 104
D.   4.5 x 10-4 32 x 103

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