Question 1

The fraction of mass in the Sun that is made of heavy elements is

Accepted Answer

A)  0.5 percent. 
B)  2 percent. 
C)  10 percent. 
D)  20 percent. 
A)  0.5 percent. 
B)  2 percent. 
C)  10 percent. 
D)  20 percent.

Question 2

The bright star named Rigel has a luminosity of   and a temperature of 11,000 K.What is its radius? Note that the temperature of the Sun is 5,800 K.

Accepted Answer

A)  5 
B)  30 
C)  70 
D)  190 
A)  5 
B)  30 
C)  70 
D)  190

Question 3

Main-sequence stars range in mass from approximately

Accepted Answer

A)    . 
B)    . 
C)    . 
D)    . 
A)    . 
B)    . 
C)    . 
D)    .

Question 4

Excluding the Sun,not a single star has an observed parallax greater than 1 arcsecond.

Accepted Answer

A) True 
 B)False

Question 5

Stars with a higher apparent brightness are necessarily closer to us than fainter stars.

Accepted Answer

A) True 
 B)False

Question 6

A star classified as a K0III star is

Accepted Answer

A)  a giant that is cooler than the Sun. 
B)  a supergiant that is hotter than the Sun. 
C)  a main-sequence star that is hotter than the Sun. 
D)  a subgiant that is cooler than the Sun. 
A)  a giant that is cooler than the Sun. 
B)  a supergiant that is hotter than the Sun. 
C)  a main-sequence star that is hotter than the Sun. 
D)  a subgiant that is cooler than the Sun.

Question 7

A star with a stellar parallax of 0.025 arcseconds is at a distance of how many parsecs?

Accepted Answer

The inverse of stell

Question 8

Which of the following properties is not plotted on the horizontal axis of an H-R diagram?

Accepted Answer

A)  Color 
B)  Luminosity 
C)  Temperature 
D)  Spectral class 
A)  Color 
B)  Luminosity 
C)  Temperature 
D)  Spectral class

Question 9

What is the spectral type of stars that have the strongest hydrogen absorption lines? Why do stars that are hotter than these have weaker hydrogen lines?

Accepted Answer

A-type stars have the strongest hydrogen

Question 10

Two main-sequence stars have the same temperature.If star A is four times brighter than star B then

Accepted Answer

A)  star B is two times farther away than star A. 
B)  star B is four times farther away than star A. 
C)  star B and Star A lie at the same distance from us. 
D)  it is impossible to determine their relative distances from the information given. 
A)  star B is two times farther away than star A. 
B)  star B is four times farther away than star A. 
C)  star B and Star A lie at the same distance from us. 
D)  it is impossible to determine their relative distances from the information given.

Question 11

The bright star Arcturus has a luminosity of   and a temperature of 4,300 K.What is its radius? Note that the Sun has a temperature of 5,800 K.

Accepted Answer

Using the Stefan-Boltzmann law

Question 12

Explain how astronomers can use the blue and visual filters to determine the temperatures of stars.

Accepted Answer

Astronomers compare the relati

Question 13

If the Hubble Space Telescope can see stars as faint as magnitude 27,how much fainter are these stars than the faintest ones you can see in a very dark night sky,which have magnitude 6?

Accepted Answer

The Hubble Space Telescope can

Question 14

Roughly what percentage of stars are main-sequence stars?

Accepted Answer

A)  10 percent 
B)  40 percent 
C)  60 percent 
D)  90 percent 
A)  10 percent 
B)  40 percent 
C)  60 percent 
D)  90 percent

Question 15

Along the main sequence,how do the luminosity,temperature,radius,and mass of stars change as you go from the upper-left to the lower-right corners of the H-R diagram?

Accepted Answer

Stars near the upper-left end

Question 16

Which sequence correctly lists the spectral classes of stars in order of decreasing temperature (from hottest to coolest)?

Accepted Answer

A)  A B F G K M O 
B)  O A B G F M K 
C)  A F O B M G K 
D)  O B A F G K M 
A)  A B F G K M O 
B)  O A B G F M K 
C)  A F O B M G K 
D)  O B A F G K M

Question 17

Star A emits its peak energy at a wavelength of 500 nm;star B emits its peak energy at a wavelength of 750 nm.If both stars have the same radii,which star is hotter and by how much?

Accepted Answer

By Wien's law,the temperature

Question 18

Star C is a red star.Star D is a blue star.Which has a larger radius?

Accepted Answer

A)  Star C 
B)  Star D 
C)  We also need to know the luminosities of the stars to determine this. 
D)  Color is not related to size at all. 
A)  Star C 
B)  Star D 
C)  We also need to know the luminosities of the stars to determine this. 
D)  Color is not related to size at all.

Question 19

Spectra of the least massive main-sequence stars show the largest amount of absorption from molecules like TiO and CN.

Accepted Answer

A) True 
 B)False

Question 20

Star E is the same temperature as star F but is four times as luminous.Which star is bigger?

Accepted Answer

A)  Star E is twice as big as star F. 
B)  Star E is four times as big as star F. 
C)  Star F is twice as big as star E. 
D)  Star F is four times as big as star E. 
A)  Star E is twice as big as star F. 
B)  Star E is four times as big as star F. 
C)  Star F is twice as big as star E. 
D)  Star F is four times as big as star E.

Exam 13: Taking the Measure of Stars

The fraction of mass in the Sun that is made of heavy elements is

The bright star named Rigel has a luminosity of and a temperature of 11,000 K.What is its radius? Note that the temperature of the Sun is 5,800 K.

Main-sequence stars range in mass from approximately

Excluding the Sun,not a single star has an observed parallax greater than 1 arcsecond.

Stars with a higher apparent brightness are necessarily closer to us than fainter stars.

A star classified as a K0III star is

A star with a stellar parallax of 0.025 arcseconds is at a distance of how many parsecs?

Which of the following properties is not plotted on the horizontal axis of an H-R diagram?

What is the spectral type of stars that have the strongest hydrogen absorption lines? Why do stars that are hotter than these have weaker hydrogen lines?

Two main-sequence stars have the same temperature.If star A is four times brighter than star B then

The bright star Arcturus has a luminosity of and a temperature of 4,300 K.What is its radius? Note that the Sun has a temperature of 5,800 K.

Explain how astronomers can use the blue and visual filters to determine the temperatures of stars.

If the Hubble Space Telescope can see stars as faint as magnitude 27,how much fainter are these stars than the faintest ones you can see in a very dark night sky,which have magnitude 6?

Roughly what percentage of stars are main-sequence stars?

Along the main sequence,how do the luminosity,temperature,radius,and mass of stars change as you go from the upper-left to the lower-right corners of the H-R diagram?

Which sequence correctly lists the spectral classes of stars in order of decreasing temperature (from hottest to coolest)?

Star A emits its peak energy at a wavelength of 500 nm;star B emits its peak energy at a wavelength of 750 nm.If both stars have the same radii,which star is hotter and by how much?

Star C is a red star.Star D is a blue star.Which has a larger radius?

Spectra of the least massive main-sequence stars show the largest amount of absorption from molecules like TiO and CN.

Star E is the same temperature as star F but is four times as luminous.Which star is bigger?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

Life

Filters