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

He I stands for...

Ionized helium.
Ionized hydrogen.
Neutral helium.

Question 2

A rotation-powered pulsar is currently 9 million years old. When it was 1 million years old, it rotated...

At the same speed.
Slower.
Faster.

Question 3

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

Iron.
Hydrogen.
Helium.

Question 4

Which is the least dense?

Earth's atmosphere
Interstellar gas
Interstellar dust

Question 5

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

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

Question 6

Compared to neutron stars, white dwarfs are...

More dense.
Less dense.
Just as dense.

Question 7

What is a Type Ia supernova?

An explosion that occurs when a new star is created.
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.

Question 8

What are the most common particles in cosmic rays?

Helium nuclei.
Protons.
Electrons or positrons.

Question 9

Which kind of region is the most common?

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

Question 10

Which of the following has the weakest magnetic field?

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

Question 11

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

Red giant.
White dwarf.
Main sequence.

Question 12

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 outermost layer.
In the core.

Question 13

Which force tries to expand every star throughout its life?

Gravity.
Electromagnetism.
Pressure.

Question 14

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

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

Question 15

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

Carbon nuclei.
Helium nuclei.
Beryllium nuclei.

Question 16

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.

Question 17

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 18

A black dwarf...

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

Question 19

Which is smaller?

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

Question 20

A reflection nebula...

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

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

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

H II regions.
Hot gas.
Molecular clouds.

Question 23

What is left after a Type Ia supernova?

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

Question 24

If a star has less mass...

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

Question 25

Can a white dwarf have 2.2 solar masses?

No.
Yes.
Depends on its radius.