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

Can a white dwarf have 1.2 solar masses?

Yes.
Depends on its radius.
No.

Question 2

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

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

Question 3

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

1.4 GHz
5.9 GHz
21 GHz

Question 4

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

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

Question 5

He II stands for...

Ionized hydrogen.
Ionized helium.
Neutral helium.

Question 6

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

Question 7

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 8

Which kind of region is the least common?

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

Question 9

The carbon atoms in your body were most likely created in...

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

Question 10

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

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

Question 11

What is interstellar extinction?

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

Question 12

A black dwarf...

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

Question 13

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

Helium nuclei.
Beryllium nuclei.
Carbon nuclei.

Question 14

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

Iron.
Hydrogen.
Helium.

Question 15

Which is bigger?

The Local Bubble.
The Local Fluff.
They are both the same size.

Question 16

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

H II regions.
Molecular clouds.
Hot gas.

Question 17

Which is the most dense?

Interstellar dust
Interstellar gas
Earth's atmosphere

Question 18

What are the least common particles in cosmic rays?

Helium nuclei.
Protons.
Electrons or positrons.

Question 19

Which force tries to expand every star throughout its life?

Pressure.
Electromagnetism.
Gravity.

Question 20

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 21

How long will a star with approximately 3.3 solar masses stay on the main sequence?

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

Question 22

What is left after a Type Ia supernova?

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

Question 23

Compared to neutron stars, white dwarfs are...

Just as dense.
More dense.
Less dense.

Question 24

Which of the following has the weakest magnetic field?

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

Question 25

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

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