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

Which of the following stars is the coolest?

K3
K9
K5

Question 2

What happens in electron-positron annihilation?

An electron and a positron annihilate each other and no photons are produced.
An electron and a positron annihilate each other and produce 1 photon.
An electron and a positron annihilate each other and produce 2 photons.

Question 3

A star was measured to have a parallax of 0.2 arc seconds. How far away is the star?

4 parsecs.
5 parsecs.
6 parsecs.

Question 4

Star A has brighter apparent magnitude than star B. What does that say about the luminosity of the two stars?

There's no way to know unless we also know the distance to each star.
Star B is more luminous.
Star A is more luminous.

Question 5

I want to measure the distance to a star that is estimated to be a few thousand light-years away. Which method should I use?

Cepheid variables
Stellar parallax
RR Lyrae variables

Question 6

A star is located on the top left of the H-R diagram. This star has...

High luminosity and high temperature.
Low luminosity and low temperature.
High luminosity and low temperature.

Question 7

Which of the following is a red dwarf?

M5 V
O4 III
G2 V

Question 8

If a particle has charge -1, what would be the charge of its antiparticle?

+1.
0.
-1.

Question 9

I see a very faint star. This could mean:

Either the distance to the star is large or the luminosity of the star is small.
Either the distance to the star is large or the luminosity of the star is large.
Either the distance to the star is small or the luminosity of the star is large.

Question 10

A proton is made of...

2 up quarks and 1 down quark.
1 up quark and 2 down quarks.
1 up quark and 1 down quark.

Question 11

In an atom, the protons are located...

Outside the nucleus.
Inside the nucleus.
Either inside or outside the nucleus, depending on the type of atom.

Question 12

If the spectral lines of a star shift toward red, this means...

The star is moving away from us.
The star is moving toward us.
The star is not moving with respect to us.

Question 13

A photon has a wavelength of 700 nm. What color is it?

Blue.
Red.
Green.

Question 14

What is nuclear fusion?

The process where light nuclei combine into heavier nuclei.
The process where heavy nuclei split into lighter nuclei.
The process where nuclei are destroyed and converted into pure energy.

Question 15

Compared to cepheid variables, RR Lyrae variables typically have...

Lower luminosity and shorter period.
Higher luminosity and longer period.
Higher luminosity and shorter period.

Question 16

Photon A has wavelength 2 cm. Photon B has wavelength 1 cm. Which photon has a higher frequency?

Photon B.
Both have the same frequency.
Photon A.

Question 17

Object A has mass 1 kg. Object B has mass 3 kg. According to E=mc², how much rest energy does object B have compared to A?

3 times less energy.
3 times more energy.
9 times more energy.

Question 18

In the H-R diagram, red dwarfs can be found...

At higher luminosity and lower temperature than the main sequence.
At higher luminosity and higher temperature than the main sequence.
On the main sequence.

Question 19

I observed an object, larger than Earth but smaller than the Sun, which generates light by deuterium fusion but not hydrogen fusion. What is it?

A brown dwarf.
A planet.
A star.

Question 20

Which of the following is the longest?

1 light-year.
1 parsec.
1 trillion kilometers.

Question 21

Which of the following stars is the least bright in the sky?

A star with apparent magnitude -4.4.
A star with apparent magnitude +3.1.
A star with apparent magnitude +7.0.

Question 22

I found a helium-9 isotope. How many neutrons does it have?

7
8
6

Question 23

Which of the following is a main-sequence star?

K6 V
B5 II
G2 IV

Question 24

What kind of mass is defined as the strength of an object's gravitational field?

Neither of the other options is correct.
Gravitational mass.
Inertial mass.

Question 25

In the proton-proton chain, how many total hydrogen nuclei do we start with? (Remember that steps 1 and 2 happen twice in a full chain!)

4.
1.
2.