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

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

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

Question 2

What is interstellar extinction?

The process where light from stars becomes dimmer.
The process where species of aliens become extinct.
The process where stars become extinct due to losing their hydrogen supply.

Question 3

Compared to white dwarfs, neutron stars are...

Just as dense.
Less dense.
More dense.

Question 4

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

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

Question 5

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

Slower.
Faster.
At the same speed.

Question 6

What are the least common particles in cosmic rays?

Helium nuclei.
Protons.
Electrons or positrons.

Question 7

If a star has more mass...

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

Question 8

Approximately how long will the Sun spend in the main sequence stage?

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

Question 9

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

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

Question 10

Which is the most dense?

Interstellar dust
Interstellar gas
Earth's atmosphere

Question 11

He II stands for...

Ionized helium.
Neutral helium.
Ionized hydrogen.

Question 12

What is left after a Type Ia supernova?

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

Question 13

Which force tries to collapse every star throughout its life?

Electromagnetism.
Pressure.
Gravity.

Question 14

What prevents a white dwarf from collapsing?

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

Question 15

The end products of the triple-alpha process are...

Carbon nuclei.
Helium nuclei.
Beryllium nuclei.

Question 16

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

Question 17

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

Hot gas.
H II regions.
Molecular clouds.

Question 18

Can a white dwarf have 2.2 solar masses?

No.
Yes.
Depends on its radius.

Question 19

Which of the following has the weakest magnetic field?

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

Question 20

Which kind of region is the least common?

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

Question 21

I saw a supernova in the sky. Where did it come from?

Material ejected from a planet near death.
Material ejected from a high-mass star near death.
Material ejected from a low-mass star near death.

Question 22

In which stage of its life will a star with mass similar to the Sun have the largest diameter?

Red giant.
White dwarf.
Main sequence.

Question 23

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

Helium.
Iron.
Hydrogen.

Question 24

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 25

A black dwarf...

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