Practice Test

Please solve the following questions. This is not a real exam, it will not be graded, and you do not need to submit your solutions to anyone. The questions are simply intended to help you practice for the real exam.

These questions will not appear in the exam itself. Students who don't genuinely attempt to solve the questions on their own, and only memorize the solutions, will have a very hard time in the actual exam!

This sample exam is online, but the real exam will be given in person, at a time and place indicated on the course website.

THIS IS NOT THE ACTUAL EXAM!
THIS IS JUST A PRACTICE EXAM!
THE REAL EXAM IS IN PERSON!

If you need any clarifications for these questions, you can ask for them on the course Teams channel.

Question 1

Which is the least dense?

Earth's atmosphere
Interstellar dust
Interstellar gas

Question 2

He II stands for...

Ionized hydrogen.
Neutral helium.
Ionized helium.

Question 3

If a star has more mass...

Its lifetime is unaffected.
Its lifetime is longer.
Its lifetime is shorter.

Question 4

An emission nebula...

Scatters light from nearby stars.
Blocks light.
Creates its own light.

Question 5

At the end of the life of a star with 20 solar masses, just before gravitational collapse, where would you expect to find iron?

In a middle layer.
In the core.
In the outermost layer.

Question 6

The atoms in a gold ring were most likely created in...

A collision with an asteroid.
A supernova.
The core of a star.

Question 7

A white dwarf...

Produces bright light with energy from nuclear reactions.
Produces faint light with stored heat energy.
Does not produce light anymore.

Question 8

What prevents a neutron star from collapsing?

Electron degeneracy pressure.
Pressure due to nuclear fusion.
Neutron degeneracy pressure and repulsion from the strong nuclear force.

Question 9

How long will a star with approximately 0.8 solar masses stay on the main sequence?

Approximately 10 million years.
Approximately 500 million years.
Approximately 14 billion years.

Question 10

In the process of star formation, after hydrogen fusion begins, we have...

A protostar.
A molecular cloud.
A main-sequence star.

Question 11

Which kind of region is the most common?

H II.
H I.
Both regions are equally common.

Question 12

What is left after a Type II supernova?

A white dwarf.
A neutron star or a black hole.
Nothing.

Question 13

Compared to white dwarfs, neutron stars are...

More dense.
Just as dense.
Less dense.

Question 14

What are the least common particles in cosmic rays?

Helium nuclei.
Protons.
Electrons or positrons.

Question 15

Approximately how long will the Sun spend in the red giant stage?

1.3 billion years.
5 million years.
11 billion years.

Question 16

What is a nova?

An explosion that occurs when a white dwarf accumulates matter from its binary companion and approaches the Chandrasekhar limit.
An explosion that occurs when a white dwarf accumulates matter from its binary companion but does not approach the Chandrasekhar limit.
An explosion that occurs when a new star is created.

Question 17

When a star is leaving the main sequence, its core is made primarily of...

Hydrogen.
Iron.
Helium.

Question 18

What is interstellar reddening?

The process where stars turn into red dwarfs.
The process where stars begin to emit more red light.
The process where light from stars becomes more red due to dust.

Question 19

A rotation-powered pulsar is currently 3 million years old. When it will be 6 million years old, it will rotate...

Faster.
At the same speed.
Slower.

Question 20

Most of the mass of interstellar gas is in the form of...

Molecular clouds.
Hot gas.
H II regions.

Question 21

Which of the following has the weakest magnetic field?

A normal (rotation- or accretion-powered) pulsar.
A magnetar.
Planet Earth.

Question 22

Can a white dwarf have 1.2 solar masses?

Depends on its radius.
Yes.
No.

Question 23

What is the frequency of light emitted in a spin-flip transition?

5.9 GHz
21 GHz
1.4 GHz

Question 24

The triple-alpha process starts by fusing together two...

Beryllium nuclei.
Carbon nuclei.
Helium nuclei.

Question 25

Consider a star with an initial mass of 15 solar masses. What will be this star's final state?

A brown dwarf.
A white dwarf.
A neutron star.