ASTRONOMY HW

Question 1

· You can calculate a star's luminosity if you know its brightness and



·	·	· size
·	·	· distance
·	·	· temperature
·	·	· velocity
·	·	· mass

· 


2 points  

Question 2

· A/an _______ star is a binary star in which the orbit plane of the two stars lies almost exactly in the line of sight of the observer.




·	·	· Apparent double star
·	·	· Eclipsing binary
·	·	· spectroscopic binary
·	·	· true binary
·	·	· visual binary

· 


1 points  

Question 3

· Two nearby stars that look like members of a binary star system but are not are called a(n)




·	·	· visual binary
·	·	· true binary
·	·	· Eclipsing binary
·	·	· spectroscopic binary
·	·	· Apparent double star

· 


1 points  

Question 4

· A map of the Sun’s magnetic field is called



·	·	· Solar seismology
·	·	· Magnetogram
·	·	· Dopplergram
·	·	· Magnetic resonance imaging
·	·	· None of the above

· 


1 points  

Question 5

· A(n) ______ is an explosion of hot gas located in the Sun's atmosphere.









·	·	· Aurora
·	·	· Coronal mass ejection
·	·	· Flare
·	·	· Prominence
·	·	· Sunspot

· 


1 points  

Question 6

· How many years a star spends in the main - sequence stage depends on its  ________.


·	·	· Density
·	·	· Luminosity
·	·	· Mass
·	·	· Temperature
·	·	· Color

· 


1 points  

Question 7

· ____ form when red giants shed their outer layers.





·	·	· Supernovae
·	·	· Novae
·	·	· Black holes
·	·	· planetary nebulae
·	·	· Protostars

· 


1 points  

Question 8

· The pressure-temperature thermostat regulates a star's



·	·	· mass
·	·	· gravity
·	·	· size
·	·	· fusion rate
·	·	· rotation speed

· 


2 points  

Question 9

· When the mass of a white dwarf becomes less than the Chandrasekhar limit, it will collapse.

True 
False 



1 points  

Question 10

· When mass is being transferred from a companion star, the spiral structure around the white dwarf from the mass falling into it is called a/an









·	·	· Accretion disk
·	·	· Light curve
·	·	· Roche lobe
·	·	· Supernova remnant
·	·	· Thermonuclear runaway

· 


1 points  

Question 11

· Cepheids can be detected further away than RR Lyrae stars.

True 
False 



1 points  

Question 12

· _____ are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy.







·	·	· Cepheid variables
·	·	· novae
·	·	· supernovae
·	·	· variable stars
·	·	· yellow giants

· 


1 points  

Question 13

· Which of these is a Type Ia Supernova?



·	·	· two stars colliding
·	·	· a red supergiant ejecting its outer layers
·	·	· a thermonuclear runaway on the surface of a white dwarf in a binary star system
·	·	· a massive star undergoing core collapse
·	·	· an explosion that destroys a white dwarf in a binary star system

· 


2 points  

Question 14

· Which of the following statements about molecular clouds is false?


·	·	· They contain helium
·	·	· The entire cloud contracts as a whole thereby leading to a gigantic protostar.
·	·	· They contain hydrogen
·	·	· They may contain iron
·	·	· They contain particles coated in ice

· 


1 points  

Question 15

· The heat emitted by a protostar comes from fusion.

True 
False 



1 points  

Question 16

· True or false

· I. Brighter stars (as seen from Earth) always have higher luminosities

· II. The more positive the magnitude, the brighter the star

· III. The Sun has a high luminosity compared to all the other stars


·	·	· Only I is false
·	·	· Only II is false
·	·	· Only III is false
·	·	· Only I and II are false
·	·	· All are false
·	·	· All are true

· 


1 points  

Question 17

· The amount of light reaching us from a star is called luminosity

True 
False 



1 points  

Question 18

· Identify the location (number) of the granulation in the schematic diagram of the Sun shown below.

·

· 


·

·	·	· 3
·	·	· 1
·	·	· 2
·	·	· 6
·	·	· 5
·	·	· 9
·	·	· 8
·	·	· 7

· 


1 points  

Question 19

· Identify the location (number) of colder areas (sunspots) in the schematic diagram of the Sun shown below.



·

·	·	· 1
·	·	· 2
·	·	· 3
·	·	· 4
·	·	· 5
·	·	· 6
·	·	· 7
·	·	· 8
·	·	· 9

· 


1 points  

Question 20

· The gradual change in the shapes of constellations is due to


·	·	· Proper motion
·	·	· Radial velocity
·	·	· Aberration of starlight
·	·	· angular shift
·	·	· transit

· 


1 points  

Question 21

· ____ devised a method using transits to determine the distance to Venus and the Sun.


·	·	· Hipparchus
·	·	· Edmund Halley
·	·	· Mason and Dixon
·	·	· Tycho Brahe
·	·	· James Bradley
·	·	· Friedrich Bessel

· 


1 points  

Question 22

·	·	· because it is a chemical process
·	·	· because that is the temperature at which neutrinos can escape
·	·	· because otherwise the Sun's gravity would stop the reaction
·	·	· because that is the temperature required to split the atom
·	·	· because that temperature is needed to overcome the repulsion between nuclei

· Why does nuclear fusion in the Sun only occur where the temperature is at least 8 million degrees Kelvin?



· 


2 points  

Question 23

· A heavy water molecule consists of oxygen and


·	·	· A Proton
·	·	· Helium
·	·	· A Neutrino
·	·	· A Neutron
·	·	· Deuterium
·	·	· A Positron

· 


1 points  

Question 24

· ______ (meaning: "Small neutral ones") are elementary particles that often travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed and are thus extremely difficult to detect.





·	·	· Isotopes
·	·	· Neutrinos
·	·	· Neutrons
·	·	· Positrons
·	·	· Protons

· 


1 points  

Question 25

· Some neutron stars have periods of just a few milliseconds.

True 
False 



1 points  

Question 26

· If the radius of a of spinning star is decreased by a factor 4, the equatorial rotational velocity (i.e. the linear velocity of a point on the star's equator)


·	·	· Increases by a factor of 2
·	·	· Increases by a factor of 4
·	·	· Decreases by a factor of 2
·	·	· Decreases by a factor of 4

· 


1 points  

Question 27

· There is a high probability that stars in a cluster will collide with each other.


True 
False 



1 points  

Question 28

· All of the following are true about star clusters except:



·	·	· Star clusters are made up of billions of stars
·	·	· Star clusters contain stars that are all nearly the same age
·	·	· Star clusters can be used to test the theory of stellar evolution
·	·	· Star clusters are formed from huge clouds of interstellar gas

· 


1 points  

Question 29

· The hypothesized collapse of a high-mass star directly to a black hole accompanied by the production of high energy jets is called





·	·	· Gamma ray burst
·	·	· Accretion disk
·	·	· Singularity
·	·	· Magnetar
·	·	· Hypernova

· 


1 points  

Question 30

· Particles that exist in tiny energy fluctuations and are then gone are called__.


·	·	· black hole particles
·	·	· virtual particles
·	·	· relative particles
·	·	· non-existent particles

· 


1 points  

Question 31

· What type of star has surface temperature between 5,000 and 6,000 K?


·	·	· O
·	·	· B
·	·	· A
·	·	· F
·	·	· G
·	·	· K
·	·	· M

· 


1 points  

Question 32

· As temperature increases, the number of collisions between atoms of a gas (here on Earth, or within a star) decreases.

True 
False 



1 points  

Question 33

· When the core of a star contracts, ___________


·	·	· it heats up
·	·	· it cools down
·	·	· its temperature does not change

· 


1 points  

Question 34

· A higher mass star does not need to be as dense as a low mass star to fuse hydrogen.

True 
False 



1 points  

Question 35

· The mass loss due to main sequence solar wind in an ordinary star like the sun is less than mass loss due to stellar wind from a dying star

True 
False 



1 points  

Question 36

· Stars the size of our sun will never have a core hot enough to fuse helium

True 
False 



1 points  

Question 37

· The main reason the spectra of different stars look noticeably different from each other is that the stars have different



·	·	· sizes
·	·	· distances
·	·	· compositions
·	·	· masses
·	·	· temperatures

· 


2 points  

Question 38

· _______ has such extraordinarily high density that the dominant contribution to its pressure arises from the exclusion principle.



·	·	· Helium gas
·	·	· Alpha particle gas
·	·	· Degenerate electron gas
·	·	· Red giant
·	·	· Shell undergoing fusion

· 


1 points  

Question 39

· Alpha particles are


·	·	· Carbon nuclei
·	·	· Hydrogen nuclei
·	·	· Helium nuclei
·	·	· Oxygen nuclei
·	·	· All of the above

· 


1 points  

Question 40

· On the H-R diagram, the horizontal axis represents


·	·	· Luminosity
·	·	· Radius
·	·	· Density
·	·	· Temperature
·	·	· Mass

· 


1 points  

Question 41

· The following diagram displays a relationship between the luminosity of stars and their temperature. Stars found in the area #1 correspond to _____


·

·	·	· Main sequence stars
·	·	· Super giants
·	·	· Red giants
·	·	· White dwarfs
·	·	· Brown dwarfs

· 


1 points  

Question 42

· The sun will become a supernova.

True 
False 



1 points  

Question 43

· In the late stages of a high-mass red giant, elements are in layers with _____ in the core and _____ in the outermost layers.


·	·	· Helium, hydrogen
·	·	· Helium, silicon
·	·	· Hydrogen, iron
·	·	· Hydrogen, oxygen
·	·	· Iron, hydrogen

· 


1 points  

Question 44

· When temperature doubles, the luminosity


·	·	· Increases 2 times
·	·	· Increases 4 times
·	·	· Increases 8 times
·	·	· Increases 10 times
·	·	· Increases 16 times
·	·	· Stays the same

· 


1 points  

Question 45

· The total light output of an object is called _________.




·	·	· Brightness
·	·	· Energy
·	·	· Luminosity
·	·	· Temperature
·	·	· none of the above

· 


1 points  

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