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 2.2 solar masses?

Depends on its radius.
No.
Yes.

Question 2

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

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

Question 3

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

Helium nuclei.
Carbon nuclei.
Beryllium nuclei.

Question 4

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

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

Question 5

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

Iron.
Hydrogen.
Helium.

Question 6

How much energy is emitted in a spin-flip transition?

5.9 micro electron volt
21 micro electron volt
1.4 micro electron volt

Question 7

What are the least common particles in cosmic rays?

Helium nuclei.
Electrons or positrons.
Protons.

Question 8

What prevents a white dwarf from collapsing?

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

Question 9

Which force tries to expand every star throughout its life?

Gravity.
Pressure.
Electromagnetism.

Question 10

He II stands for...

Ionized hydrogen.
Neutral helium.
Ionized helium.

Question 11

Which is the least dense?

Interstellar dust
Earth's atmosphere
Interstellar gas

Question 12

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

Red giant.
Main sequence.
White dwarf.

Question 13

Which is smaller?

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

Question 14

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

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

Question 15

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

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

Question 16

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

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

Question 17

Which of the following has the strongest magnetic field?

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

Question 18

A black dwarf...

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

Question 19

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

Slower.
At the same speed.
Faster.

Question 20

If a star has more mass...

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

Question 21

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

Question 22

What is a Type Ia supernova?

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 white dwarf accumulates matter from its binary companion and approaches the Chandrasekhar limit.
An explosion that occurs when a new star is created.

Question 23

What is interstellar reddening?

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

Question 24

What is left after a Type Ia supernova?

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

Question 25

Compared to neutron stars, white dwarfs are...

More dense.
Just as dense.
Less dense.