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

What is a Type Ia supernova?

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 2

Which is smaller?

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

Question 3

I saw a supernova 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 4

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

H II regions.
Hot gas.
Molecular clouds.

Question 5

Can a white dwarf have 2.2 solar masses?

No.
Yes.
Depends on its radius.

Question 6

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

Helium nuclei.
Carbon nuclei.
Beryllium nuclei.

Question 7

Which is the most dense?

Interstellar dust
Interstellar gas
Earth's atmosphere

Question 8

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

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

Question 9

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

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

Question 10

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 11

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

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

Question 12

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

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

Question 13

A reflection nebula...

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

Question 14

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 a middle layer.
In the outermost layer.

Question 15

If a star has less mass...

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

Question 16

What is left after a Type II supernova?

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

Question 17

What prevents a white dwarf from collapsing?

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

Question 18

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

Helium.
Iron.
Hydrogen.

Question 19

Compared to neutron stars, white dwarfs are...

More dense.
Just as dense.
Less dense.

Question 20

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

21 GHz
1.4 GHz
5.9 GHz

Question 21

What are the most common particles in cosmic rays?

Protons.
Electrons or positrons.
Helium nuclei.

Question 22

In the process of star formation, after a core starts contracting but before hydrogen fusion begins, we have...

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

Question 23

He I stands for...

Neutral helium.
Ionized helium.
Ionized hydrogen.

Question 24

Which of the following has the strongest magnetic field?

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

Question 25

Which force tries to expand every star throughout its life?

Pressure.
Gravity.
Electromagnetism.