Question 1

The nucleus of the hydrogen atom consists of a single neutron.

Accepted Answer

A) True 
 B)False

Question 2

Why do nuclear reactions in a star occur only near its centre?

Accepted Answer

Nuclear reactions in a star primarily oc

Question 3

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

Accepted Answer

A) brown dwarfs 
B) Herbig-Haro objects 
C) Bok globules 
D) T Tauri stars 
A) brown dwarfs 
B) Herbig-Haro objects 
C) Bok globules 
D) T Tauri stars

Question 4

Some massive stars only live a few million years.

Accepted Answer

A) True 
 B)False

Question 5

As a star begins to form,what is its primary energy source?

Accepted Answer

A) nuclear fusion 
B) nuclear fission 
C) gravitational potential energy 
D) magnetic fields 
A) nuclear fusion 
B) nuclear fission 
C) gravitational potential energy 
D) magnetic fields

Question 6

The dust in the interstellar medium can make distant stars look redder than they really are.

Accepted Answer

A) True 
 B)False

Question 7

Absorption lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of a very low density.How do they show this?

Accepted Answer

A) The lines are blue shifted. 
B) The lines are red shifted. 
C) The lines are extremely broad. 
D) The lines are extremely narrow. 
A) The lines are blue shifted. 
B) The lines are red shifted. 
C) The lines are extremely broad. 
D) The lines are extremely narrow.

Question 8

What happens in the proton-proton chain?

Accepted Answer

A) Two protons are fused to make a helium nucleus. 
B) Three protons are fused to make a lithium nucleus. 
C) A helium nucleus is split into four protons. 
D) Four protons are fused to make a helium nucleus. 
A) Two protons are fused to make a helium nucleus. 
B) Three protons are fused to make a lithium nucleus. 
C) A helium nucleus is split into four protons. 
D) Four protons are fused to make a helium nucleus.

Question 9

What causes the dimming of starlight in the interstellar medium?

Accepted Answer

A) dust particles 
B) ionized hydrogen 
C) neutral hydrogen 
D) molecular gas 
A) dust particles 
B) ionized hydrogen 
C) neutral hydrogen 
D) molecular gas

Question 10

Energy flows by radiation or convection inside stars but almost never by conduction.

Accepted Answer

A) True 
 B)False

Question 11

Stars with masses below a certain threshold produce most of their energy via the proton-proton chain.What is that threshold?

Accepted Answer

A) 0.01 solar masses 
B) 0.1 solar masses 
C) 1.1 solar masses 
D) 11 solar masses 
A) 0.01 solar masses 
B) 0.1 solar masses 
C) 1.1 solar masses 
D) 11 solar masses

Question 12

In an H-R diagram,pre-main-sequence stars are above and to the right of the main sequence.

Accepted Answer

A) True 
 B)False

Question 13

Stars of spectral type K have strong Balmer lines.

Accepted Answer

A) True 
 B)False

Question 14

What happens in the carbon-nitrogen-oxygen (CNO)cycle?

Accepted Answer

A) Carbon nuclei are split 3 ways to make helium nuclei. 
B) Carbon and oxygen combine to form nitrogen, which produces energy. 
C) Carbon and nitrogen combine to form oxygen and energy. 
D) Four hydrogen nuclei combine to form one helium nucleus and energy. 
A) Carbon nuclei are split 3 ways to make helium nuclei. 
B) Carbon and oxygen combine to form nitrogen, which produces energy. 
C) Carbon and nitrogen combine to form oxygen and energy. 
D) Four hydrogen nuclei combine to form one helium nucleus and energy.

Question 15

The Sun has a core in which energy travels outward primarily by radiation.

Accepted Answer

A) True 
 B)False

Question 16

Why are reflection nebulae blue in colour?

Accepted Answer

Reflection nebulae are blue in color pri

Question 17

Why do nuclear fusion reactions only take place in the interior of a star?

Accepted Answer

A) The magnetic fields are strongest there. 
B) The temperature and density are highest in the centre. 
C) The core is the only place where hydrogen is found. 
D) The strong nuclear force is only active in the centres of stars. 
A) The magnetic fields are strongest there. 
B) The temperature and density are highest in the centre. 
C) The core is the only place where hydrogen is found. 
D) The strong nuclear force is only active in the centres of stars.

Question 18

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

Accepted Answer

A) True 
 B)False

Question 19

The formation of one of the following phenomena requires that a young hot star (T =25,000 K)be relatively close by.Which one?

Accepted Answer

A) emission nebulae 
B) HI regions 
C) molecular clouds 
D) 21-centimetre radiation 
A) emission nebulae 
B) HI regions 
C) molecular clouds 
D) 21-centimetre radiation

Question 20

What does the strong force do?

Accepted Answer

A) It binds electrons to the nucleus in an atom. 
B) It holds the Moon in orbit around the Earth. 
C) It creates the magnetic field associated with sunspots. 
D) It binds protons and neutrons together to form a nucleus. 
A) It binds electrons to the nucleus in an atom. 
B) It holds the Moon in orbit around the Earth. 
C) It creates the magnetic field associated with sunspots. 
D) It binds protons and neutrons together to form a nucleus.

The nucleus of the hydrogen atom consists of a single neutron.

Why do nuclear reactions in a star occur only near its centre?

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

Some massive stars only live a few million years.

As a star begins to form,what is its primary energy source?

The dust in the interstellar medium can make distant stars look redder than they really are.

Absorption lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of a very low density.How do they show this?

What happens in the proton-proton chain?

What causes the dimming of starlight in the interstellar medium?

Energy flows by radiation or convection inside stars but almost never by conduction.

Stars with masses below a certain threshold produce most of their energy via the proton-proton chain.What is that threshold?

In an H-R diagram,pre-main-sequence stars are above and to the right of the main sequence.

Stars of spectral type K have strong Balmer lines.

What happens in the carbon-nitrogen-oxygen (CNO)cycle?

The Sun has a core in which energy travels outward primarily by radiation.

Why are reflection nebulae blue in colour?

Why do nuclear fusion reactions only take place in the interior of a star?

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

The formation of one of the following phenomena requires that a young hot star (T =25,000 K)be relatively close by.Which one?

What does the strong force do?

The Scale of the Cosmos

User's Guide to the Sky

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments

Sun Light and Sun Atoms

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

The Origin of the Solar System

Comparative Planetology of the Terrestrial Planets

Comparative Planetology of the Jovian Planets

Life on Other Worlds

Filters

Exam 7: The Structure and Formation of Stars

The nucleus of the hydrogen atom consists of a single neutron.

Why do nuclear reactions in a star occur only near its centre?

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

Some massive stars only live a few million years.

As a star begins to form,what is its primary energy source?

The dust in the interstellar medium can make distant stars look redder than they really are.

Absorption lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of a very low density.How do they show this?

What happens in the proton-proton chain?

What causes the dimming of starlight in the interstellar medium?

Energy flows by radiation or convection inside stars but almost never by conduction.

Stars with masses below a certain threshold produce most of their energy via the proton-proton chain.What is that threshold?

In an H-R diagram,pre-main-sequence stars are above and to the right of the main sequence.

Stars of spectral type K have strong Balmer lines.

What happens in the carbon-nitrogen-oxygen (CNO)cycle?

The Sun has a core in which energy travels outward primarily by radiation.

Why are reflection nebulae blue in colour?

Why do nuclear fusion reactions only take place in the interior of a star?

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

The formation of one of the following phenomena requires that a young hot star (T =25,000 K)be relatively close by.Which one?

What does the strong force do?

The Scale of the Cosmos

User's Guide to the Sky

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments

Sun Light and Sun Atoms

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

The Origin of the Solar System

Comparative Planetology of the Terrestrial Planets

Comparative Planetology of the Jovian Planets

Life on Other Worlds

Filters