Name: 
 

EXAM 2:   Astronomy of Stars, Galaxies & Cosmology



Completion
Complete each sentence or statement.
 

 1. 

The _______________ of the sun is composed of ionized gas and produces a continuous spectrum with a superimposed emission spectrum.
 

 

 2. 

A G2 I star is _______________ in diameter and _______________ luminous than the sun.
 

 

 3. 

The parallax of the star 75 Leo is 0.10, and its apparent visual magnitude is +5.18. The absolute visual magnitude of 75 Leo is _______________.
 

 

 4. 

_______________ can be used to determine the distance to a star when the spectrum of the star can be used to determine its spectral type and luminosity class.
 

 

 5. 

Most of the light we see coming from the sun originates in the _______________.
 

 

 6. 

Luminosity class IV objects are known as _______________.
 

 

True/False
Indicate whether the sentence or statement is true or false.
 

 7. 

Most of the visible light from the sun originates in the photosphere.
 

 8. 

A star whose parallax is 0.01 seconds of arc is at a distance of 1,000 pc.
 

 9. 

White dwarfs have such a low luminosity that even the nearest white dwarfs are not visible to the naked eye.
 

 10. 

Sunspots are hotter than the photosphere.
 

 11. 

The absolute magnitude of a star is the apparent magnitude it would have if it were 10 pc from Earth.
 

 12. 

Supergiants are about as common as the sun.
 

 13. 

The location of a star in the HR diagram indicates its temperature and intrinsic brightness.
 

 14. 

The most common kinds of stars are low-luminosity stars.
 

 15. 

The corona is heated by the solar magnetic field.
 

 16. 

Giant stars are members of luminosity class III.
 

 17. 

If a star is twice as hot as the sun and only half the sun's diameter, it will be less luminous than the sun.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 18. 

A star's absolute magnitude depends only on the star's
a.
temperature and diameter.
b.
distance and diameter.
c.
distance.
d.
temperature and distance.
e.
apparent magnitude.
 

 19. 

Sunspots are known to be magnetic phenomena because
a.
the Zeeman effect is observed in sunspots.
b.
collisional broadening is observed in spectral lines.
c.
observations during eclipses reveal a very extensive photosphere.
d.
infrared observations indicate that the sunspots are cooler than their surroundings.
e.
Doppler shifts in spectral lines are observed.
 

 20. 

Absolute visual magnitude is
a.
the luminosity of a star observed from a distance of 1000 pc.
b.
the apparent magnitude of a star observed from Earth.
c.
the apparent magnitude of a star observed from a distance of 10 pc.
d.
the luminosity of a star observed from Earth.
e.
c and d
 

 21. 

The centers of granules
a.
are brighter and cooler than their surroundings.
b.
are cool material falling from the photosphere to the regions below.
c.
are hot material rising to the photosphere from below.
d.
show strong Zeeman effects.
e.
are fainter and hotter than their surroundings.
 

 22. 

If a star with an absolute magnitude of -5 has an apparent magnitude of +5, then its distance is
a.
100 pc.
b.
10 pc.
c.
1000 pc
d.
10,000 pc.
e.
1 pc.
 

 23. 

Sunspots
a.
are hotter than their surroundings.
b.
show the Zeeman effect indicating the presence of strong magnetic fields.
c.
are regions where material is rising from below the photosphere.
d.
produce spicules.
e.
are generally found near the poles of the sun during sunspot maximum.
 

 24. 

Sheat is an M2 II star. Based on this information which of the following are true?

I.
Sheat has a surface temperature less than the sun.
II.
Sheat has a diameter that is greater than that of the sun.
III.
Sheat is more luminous than the sun.
IV.
Sheat is located near the upper left hand corner in the HR diagram.
a.
I, II, & III
b.
I, II, III, & IV
c.
II, III, & IV
d.
II & IV
e.
I & II
 

 25. 

Which star in the HR Diagram above is most like the sun?
a.
Sirius B
b.
Arcturus
c.
HR 5337
d.
Antares
e.
Alnilam
 

 26. 

Which star in the HR Diagram above has the greatest surface temperature?
a.
Antares
b.
Arcturus
c.
Sirius B
d.
HR 5337
e.
Alnilam
 

 27. 

Which of the stars in the HR Diagram above has the largest absolute visual magnitude?
a.
Antares
b.
Arcturus
c.
HR 5337
d.
Sirius B
e.
Alnilam
 

 28. 

Vega is an A0 V star. Based on this information which of the following are true?

I.
Vega has a surface temperature less than the sun.
II.
Vega has a mass that is greater than that of the sun.
III.
Vega is more luminous than the sun.
IV.
Vega is located near the upper left hand corner in the HR diagram.
a.
II, III, & IV
b.
I, II, & III
c.
II & III
d.
I & II
e.
I, II, III, & IV
 

 29. 

In an H-R Diagram, stars with the smallest radius are found in the _______________ of the diagram.
a.
lower left corner
b.
upper right corner
c.
center
d.
lower right corner
e.
upper left corner
 

 30. 

Most of the light we see coming from the sun originates in the
a.
magnetic field.
b.
photosphere.
c.
chromosphere.
d.
corona.
e.
sunspots.
 

 31. 

Which star in the Star Table above has the greatest diameter?
a.
65 Tau
b.
HR 2491
c.
HR 4621
d.
58 Ori
e.
sgc_exam_2_web_files/i0340000.jpg Pic
 

 32. 

Which star in the Star Table above is the closest to Earth?
a.
HR 2491
b.
HR 4621
c.
sgc_exam_2_web_files/i0350000.jpg Pic
d.
58 Ori
e.
65 Tau
 

 33. 

Which star in the Star Table above has the greatest surface temperature?
a.
65 Tau
b.
HR 2491
c.
58 Ori
d.
HR 4621
e.
sgc_exam_2_web_files/i0360000.jpg Pic
 

 34. 

Which star in the Star Table above would appear the faintest in the night sky?
a.
sgc_exam_2_web_files/i0370000.jpg Pic
b.
HR 2491
c.
58 Ori
d.
HR 4621
e.
65 Tau
 

 35. 

Which star in the Star Table above has the greatest luminosity?
a.
sgc_exam_2_web_files/i0380000.jpg Pic
b.
HR 4621
c.
HR 2491
d.
65 Tau
e.
58 Ori
 

 36. 

The United States consumes 2.5sgc_exam_2_web_files/i0390000.jpg1019 J of energy each year. A typical solar flare releases 5.0sgc_exam_2_web_files/i0390001.jpg1024 J of energy. How many years could we run the United States on the energy released by this solar flare if all of the released energy could be used?
a.
500 years
b.
200,000 years
c.
1.25sgc_exam_2_web_files/i0390002.jpg1044 years
d.
5sgc_exam_2_web_files/i0390003.jpg10-6 years
e.
about 12 years
 

 37. 

If a star has a parallax of 0.02 seconds of arc, then its distance will be
a.
5 pc
b.
2 pc
c.
50 pc
d.
500 pc
e.
20 pc
 

 38. 

Giant stars are

I.
more luminous than the sun.
II.
larger in diameter than the sun.
III.
Cooler than B stars.
IV.
located above the main sequence stars in the H-R diagram.
a.
II & IV
b.
I, II, III, & IV
c.
II, III, & IV
d.
I & II
e.
I, II, & IV
 

 39. 

We know that giant stars are larger in diameter than the sun because
a.
they are more luminous but have about the same temperature.
b.
they are cooler but have about the same luminosity.
c.
they are less luminous but have about the same temperature.
d.
they have a larger absolute magnitude than the sun.
e.
they are hotter but have about the same luminosity.
 

 40. 

The most recent sunspot maximum occurred in 2001, when is the next sunspot maximum expected if the solar cycle continues?
a.
2012
b.
2023
c.
2006
d.
The last cycle started a Maunder minimum, and the next maximum can not be predicted.
e.
1990
 

 41. 

The most common stars are
a.
upper main sequence stars.
b.
lower main sequence stars.
c.
supergiants.
d.
giants.
e.
white dwarfs.
 

 42. 

In the H-R diagram, 90 percent of all stars are
a.
among the G stars.
b.
among the B stars.
c.
in the supergiant region.
d.
on the main sequence.
e.
in the giant region.
 

 43. 

The sunspot cycle affects

I.
the latitude at which sunspots are visible at a given time.
II.
the number of sunspots that are visible at a given time.
III.
the rotation rate of the sun's equator at a given time.
IV.
the magnetic polarity of the sunspots at a given time.
a.
I & IV
b.
I, II, & IV
c.
II & III
d.
I & II
e.
I, II & III
 

 44. 

Sunspots are dark because
a.
shock waves move through the photosphere.
b.
the strong magnetic field inhibits the currents of hot gas rising from below.
c.
the sun rotates differentially.
d.
they radiate their energy into space faster than the rest of the photosphere.
e.
regions of the photosphere are obscured by material in the chromosphere.
 

 45. 

Granulation is caused by
a.
the heating in the chromosphere.
b.
sunspots.
c.
shock waves in the corona.
d.
rising gas below the photosphere.
e.
the solar wind flowing away from the corona.
 

 46. 

In some regions of the corona, the magnetic field does not loop back to the sun, and the gas escapes unimpeded. These regions are called _______________ and are believed to be the source of the solar wind.
a.
granules
b.
flares
c.
coronal holes
d.
prominences
e.
auroras
 

 47. 

Groombridge 34 is an M1 V star. Based on this information, which of the following are true?

I.
Groombridge 34 has a surface temperature that is less than the sun.
II.
Groomgridge 34 has a mass that is greater than that of the sun.
III.
Groombridge 34 is less luminous than the sun.
IV.
Groombridge 34 is located near the middle of the HR diagram.
a.
II & IV
b.
I & III
c.
I & IV
d.
II & III
e.
I & II
 

 48. 

The distance to Rigel is 250 pc. Which of the following statements is true based on this information?
a.
Rigel is located in the upper right corner of the HR diagram.
b.
The absolute bolometric magnitude of Rigel is nearly equal to its absolute visual magnitude.
c.
The distance to Rigel can be determined by measuring its parallax.
d.
Rigel's apparent visual magnitude has a smaller value than its absolute visual magnitude.
e.
none of the above
 



 
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