Astronomy 102_01                                                                                     Name_____________

 

Final (v1)

 

Be sure to write your first and last name on the computer sheet and bubble it in.  Also you will need to record the version of the final (v1 or v2) next to test on the computer sheet. For each multiple choice question, pick the best answer and record it on the computer sheet.

 

1.       Infrared stars within the Orion Nebula are examples of which stage of stellar evolution?

(a)    supernova remnants  (b) protostar and young star  (c) red giant  (d) planetary nebula

(e)    old dying stars

 

2.  Astronomers believe there are large amounts of invisible dark matter in the Universe to explain    (a)  the rotation curves of galaxies     (b)  star formation   (c)  why clusters of galaxies don't fly apart    (d)  (a) and (c) above    (e)  all of the above

 

3.       Recall that on earth our weight is due to the force of gravity exerted on us by the earth.  Suppose you visited another planet with an identical mass as the earth but a radius that was three times as large.  By what factor would your weight change if you were standing on the surface of this planet?

(a) 9 times greater    (b) 3 times greater  (c) no change   (d) 3 times less  (e) 9 times less

 

4.       In your homework, you determined the mass of the suspected black hole in the center of our galaxy using

(a) Newton's 1st law   (b) Kepler's 3rd law   (c) Kirchhoff's law  (d) Mass-luminosity relation

(e) dark matter mass data

 

5.       Next Monday will be the spring equinox.  If you stood at the north pole on this day, what angle would the sun make with respect to the horizon?

(a) 23 1/2o above   (b) 23 1/2o below    (c) 0o    (d) 90o   (e) 35o

 

6.   Which way do the stars appear to move about polaris for a viewer on earth in the northern hemisphere?   (a) clockwise   (b) counterclockwise

 

7.       Comparing spectra of the red giant star Arcturus with spectral class B stars in the Pleiades star cluster reveals the wavelength of greatest intensity for Arcturus is

(a) shorter   (b) longer  (c)  same  (d) cannot be determined from the information given

 

8.       The velocity of galaxies receding away from us can be determined using

(a)    Doppler's formula and the redshifted 21cm line of hydrogen

(b)    Doppler's formula and the blueshifted 21cm line of hydrogen

(c)    Hubble's law and the redshifted 21cm line of hydrogen

(d)    Hubble's law and the blueshifted 21cm line of hydrogen

(e)    None of the above

 

9.       The Earth would not have seasons if

a)      Its axis of rotation were perpendicular to its equatorial plane

b)      The observers zenith were perpendicular to the Earth's orbital plane

c)      Its equatorial plane were perpendicular to its orbital plane

d)      Its axis of  rotation were perpendicular to its orbital plane

e)      Its orbit around the Sun were perfectly circular

 

 

 

 

10.   Radio waves travel through space at what speed?

a)      much faster than the speed of light

b)      at the speed of light

c)      slightly faster than the speed of light, because their wavelength is longer

d)      slightly slower than the speed of light, because their wavelength is longer

e)      much slower than the speed of light

 

11.  The mass of four hydrogen atoms is 6.693x10-27kg and the mass of one helium atom is 6.645x10-27kg.  How much energy is released every time one helium atom is made in the center of our sun?  (a)  4.3x10-12 J   (b) 6.0x10-10 J  (c) 4.3x10-10 eV   (d) 4.3x10-10 eV  (e) none of the above

 

12.   What causes the granular appearance on the surface of the Sun?

(a)    Hot spots caused by thermonuclear fusion just below the Sun's surface

(b)    Convective motion under the solar surface

(c)    The regular impact of meteoroids and comets onto the solar surface.

(d)    Differential rotation of the surface layers

(e)    Irregularities in the surface due to the Sun's rotation

 

13.   If the density of our Universe is less than the critical density,

a)      the Universe will just barely expand forever

b)      the Universe will easily expand forever

c)      the Universe will expand to reach a maximum size and then collapse back on itself

d)      star formation could have never taken place

e)      dark matter plays a small role in the total mass of the Universe

 

14.   An arching column of gas suspended over a sunspot group is called a

(a) spicule   (b) corona hole  (c) mass ejection  (d) flare  (e)  prominence

 

15.   What radiation ionizes the hydrogen in an HII region?

(a)    Ultraviolet radiation form O and B stars

(b)    X rays from the coronas of solar-type stars

(c)    Infrared radiation from pre-main-sequence stars

(d)    Gamma rays from neutron stars

(e)    X rays from neutron stars

 

16.   The neutrino is

a)      a particle that is believed to be created in the suns core but has never been detected

b)      a very small neutral particle that is easily detected

c)      a heavy, uncharged nuclear particle that is difficult to detect

d)      another name for an electron that carries a positive charge instead of a negative charge

e)      an elusive subatomic particle having little or no mass

 

17.   Which of the following in not a characteristic of a quasar?

(a) non-thermal spectrum   (b) very luminous  (c) large redshift  (d) found near our galaxy

(e)  large recessional velocity

 

 

18.   Stellar parallax is

a)      the assumed change in the distance to a star when it dims as it passes through an interstellar cloud

b)      the shifting position of a star in space due to its orbital motion about another star

c)      the elliptical motion of a star in a binary system, as the two stars orbit around each other

d)      the difference between the apparent magnitude and the absolute magnitude of a star

e)      the apparent shift in the position of a nearby star because of the Earth's motion in its orbit

 

19.   A reflection nebula is made visible by

a)      light from embedded stars reflected over a wide range of wavelengths toward Earth by crystals of water, methane and ammonia ices

b)      thermal energy emitted as a continuous spectrum by the very hot gas, much like that emitted by a hot body on Earth

c)      emission lines from hydrogen, which itself has been ionized by UV light

d)      blue light preferentially scattered by dust grains

e)      none of the above

 

20.   Big Bang nucleosynthesis explains

a)      the primordial abundance of iron in the Universe

b)      the primordial abundance of helium in the Universe

c)      the abundance of iron in the Universe

d)      the abundance of elements heavier than iron in the Universe

e)      the abundance of all elements found in the Universe

 

21.   The phenomenon of precession of the Earth's spin axis is caused by

a)      the gravitational pull of the Moon and Sun upon the Earth's equatorial bulge

b)      the tidal ebb and flow of ocean waters upon Earth

c)      the varying intensity of sunlight upon Earth throughout the year

d)      the variation of the spin rate of Earth

e)      the motion of the Earth along its orbital path around the sun

 

22.   If the Hipparchos satellite measures the parallax  of a star to be 0.008 arc second, how far is that star from us?

a) 125 ly            b) 125 pc         c) 8000 pc         d) 8000 ly          e) 0.008 pc

 

23.   Luminosity of a star can be determined by knowing the stars

a)      distance and apparent brightness 

b)      temperature and physical size

c)      spectral class and luminosity class

d)      a) and c) above

e)      a), b) and c) above

 

24.  The star a Centauri C and the star Groombridge 34B have the same apparent brightness, but a Centauri C is 1.3 pc away for the Earth while Groombridge 34B is 3.5 pc away.  What is the luminosity of Groombridge 34B, compared to that of a Centauri C?

a)      7.25 times fainter

b)      2.69 times fainter

c)      the same

d)      2.69 times brighter

e)      7.25 times brighter

 

25.   A cool, transparent gas in front of a source of a continuous spectrum produces

a)      an absorption spectrum

b)      an emission spectrum

c)      a continuous spectrum

d)      a combination of all three types of spectrum

e)      a combination of emission spectrum and absorption spectrum

 

26.   Apparent magnitude is a measure of

a)      the brightness of a star, as seen from Earth

b)      the temperature of a star

c)      the size (diameter) of a star

d)      the surface brightness of a star

e)      the apparent magnitude of a star if it were 10 pc from the Earth

 

27.   A certain galaxy s observed to be receding from the Sun at a rate of 75,000 km/s.  The distance to this galaxy is measured independently to be 1.5x109pc. Base on this data what is the value of the Hubble constant?

a)  65 km/s/Mpc  b) 50 km/s/Mpc   c)  75 km/s/Mpc   d)  112 km/s/Mpc   e) none of the above

 

28.  Betelgeuse (the bright star in the constellation Orion) has a surface temperature of 3300K and a luminosity 100,000 times that of the Sun.  What is its approximate radius, in terms of that of the Sun?

a)      10 times larger

b)      the same

c)      100 times larger

d)      1000 times larger

e)      10,000 times larger

 

29.   Which of the following main sequence stars will have the greatest mass?

a) M         b) G         c) A       d) B             e) K

 

30.   The spectral-luminosity class of the star Spica is B1 V and that of the star t Ceti is G8 V. From this information, we know for sure that

a)      t Ceti is hotter and has a larger luminosity than Spica

b)   t Ceti is hotter and has a lower luminosity than Spica

c)   t Ceti is hotter and has the same luminosity as Spica

d)   t Ceti is cooler but has the same luminosity as Spica

e)   t Ceti is cooler and has a lower luminosity than Spica

 

31.   On December 1 at 10:00 p.m. you observe the bright star Procyon to be just rising over the eastern horizon.  At approximately what time would you see this star rising ten days later?

a)      10:10 p.m.      b)  9:50 p.m.      c) 10:00 p.m.      d) 10:40 p.m.      e) 9:20 p.m.

 

32.   The spectrum of light from the Sun's corona seen during a total eclipse is

a)      an absorption spectrum

b)      an emission spectrum

c)      a continuous spectrum

d)      a combination of all three types of spectrum

e)      a combination of emission spectrum and absorption spectrum

 

33.   The difference between the full 22 year sunspot cycle and the 11 year sunspot cycle is related to which of the following facts

a)   sunspots reverse magnetic polarity after 11 years

b)      sunspots take 11 years to migrate toward the equator and another 11 years to migrate back to towards the poles

c)      sunspots appear at mid-latitudes and migrate towards the equator

d)      it takes 11 years for a sunspot to go halfway around the sun and 22 years for a full cycle

e)      none of the above

 

34.   A white dwarf star is

a)      a  starring character in a new Walt Disney production involving snow white and the seven dwarfs

b)      the likely fate of our Sun

c)      a little man who hangs around peoples gardens

d)      the likely fate of a star with a main-sequence mass greater than eight solar masses

e)      b) and d) above

 

35.   The main-sequence star Sirius A (mass approximately 2.8 times the sun's mass) and its binary companion Sirius B, a white dwarf star, could in the future become a

a) nova      b)  supernova    c) planetary nebula   d) a) and b) above  e) all of the above

 

36.   Of the following main-sequence spectral classes, A, B, G, M, O, which will have the longest main-sequence lifetime?

a) A     b) B            c) G             d) M             e) O

 

37.   The radius of the supergiant Antares in the constellation of scorpio is approximately 7.5x108km.  What is the radius of Antares in AU?

a) 1.1x1017AU     b) 5 AU             c) 10 AU       d) 5.0x1016AU         e) none of the above

 

38.   The upper mass limit for a neutron star is approximately

a) three solar masses             b) four solar masses             c) eight solar masses             d) 1.4 solar masses  

e) none of the above

 

39.   Spectroscopic parallax is a powerful technique for finding distances to objects in remote parts of our galaxy.  Employing the technique, an astronomer carefully measures a stars spectral type and luminosity class.  Using information from an H-R diagram and what other piece of information to find the distance.

a) luminosity             b) temperature             c) size             d) apparent brightness             e) mass

 

40.   Which of the following is not a property of a neutron star.

a) electron degeneracy  b) superfluid interior c) superconducting interior d) rapid rotation  e)small

 

41.   Using the Hubble constant (65 km/s/Mpc) to estimate the age of the Universe gives an age of

a)      25 billion years  b) 8 billion years  c) 10 million years  d) 13 million years  e) 15 billion years

 

42.   A main-sequence star with a mass greater than eight solar masses is not expected to be a

a) red giant             b) supergiant             c) supernova            d) neutron star            e) planetary nebula

 

43.   Population II stars are commonly found in

a)      newly formed star clusters  b) the galactic disk  c) the galactic halo  d) HII regions  e) none of the above

 

44.   Elements heavier than iron such as copper, gold and lead found here on earth are believed to be created

a)      by fusion reactions taking place in low mass stars

b)      by fission reactions taking place in low mass stars

c)      by fusion reactions taking place in high mass stars

d)      by fission reactions taking place in high mass stars

e)       by supernova explosions and processes thereafter

 

45.   Which of the following is not a prediction of Einstein's General Theory of Relativity

a)      Bending of light in a gravitational field

b)      Precession of perihelion of Mercury's orbit

c)      Black hole

d)      Gravitational redshift

e)      Moving objects contract in the direction of their motion

 

46.   Mass transfer from a companion star to a neutron star can result in

a)      a faster spinning neutron star  b) x-ray bursters  c) x-ray pulsars  d) all of the above  e) none of the above

 

47.   One of the postulates of Einstein's Special Theory of Relativity is

a)      the speed of light in vacuum is the same for all observers

b)      moving clocks run more slowly

c)      the laws of physics depend on an observers motion

d)      light is quantized

e)      none of the above

 

48.   Photons from which part of the electromagnetic spectrum carry the most energy

a) blue light    b) red light    c) ultraviolet light    d) x-rays     e) infrared light

 

49.   When plotted on an H-R diagram, a particular star cluster has its more massive stars above the main-sequence and its less massive stars on the main sequence.  From this information can we estimate the age of the cluster?

a)      No

b)      Yes, the age of the cluster is approximately the main-sequence lifetime of the least massive star on the main-sequence

c)      Yes, the age of the cluster is approximately the main-sequence lifetime of the most massive star

d)      Yes, the age of the cluster is approximately the main-sequence lifetime of the least massive star

e)      Yes, the age of the cluster is approximately the main-sequence lifetime of the star that has just left the main-sequence

 

50.  The two forces producing hydrostatic equilibrium in a white dwarf are

(a) gravity and gas pressure   (b) nuclear forces and gravity  (c) electron degeneracy pressure and gravity    (d)  electrical forces and gas pressure  (e) electrical forces and nuclear forces.

 

51.  Given that a type Ia supernova results from an exploding white dwarf star, what is the

primary difference between the type II, Ib and Ic supernova's?

(a) main-sequence mass     (b) spectra     (c) outer layers present when the star explodes

(d) all of the above  (e) b and c above

 

52.   The predominant color of an HII region is

a)      green-yellow, from the 530.3nm emission line of ionized iron, equivalent to that from the hot solar corona

b)      a continuum of colors, the combined light from the stars in the region

c)      blue, from the scattering of light from hot stars by dust particles

d)      red, from the Balmer Ha line

e)      yellow, from sodium emission lines

 

53.  By observing Cepheid stars in the Andromeda galaxy, Hubble was able to show that Andromeda was not a nebula in our galaxy.  What information regarding Cepheid stars from the list below did Hubble use to prove this result.

a) temperature  b)  apparent brightness  c) mass-luminosity relation  d) radius  e)  mass

 

54.   A pulsar is believed to be

a)      a kind of car that came from another galaxy

b)      a rotating quasar with its jet periodically aligning with our line of sight

c)      a rapidly rotating neutron star with magnetic axis periodically aligning with our line of sight

d)      a star that changes size regularly causing a regular pulsing change in its luminosity

e)      an eclipsing binary star system causing a regular pulsing change in its luminosity

 

55.   Which of the following is not expected to be a mechanism that initiates star formation

a)      supernova explosions

b)      density waves in spiral galaxies

c)      expanding planetary nebula

d)      stellar winds from O and B type stars

e)      colliding molecular clouds

 

56.   The large-scale distribution of galaxies is