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 happens in electron-positron annihilation?

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

Question 2

Which of the following stars is the hottest?

K3
K9
K5

Question 3

A star was measured to have a parallax of 0.25 arc seconds. How far away is the star?

5 parsecs.
6 parsecs.
4 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

A photon has a wavelength of 530 nm. What color is it?

Green.
Blue.
Red.

Question 6

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

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

Question 7

In an atom, the protons are located...

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

Question 8

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

0.
-1.
+1.

Question 9

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!)

1.
4.
2.

Question 10

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

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

Question 11

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

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

Question 12

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

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

Question 13

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

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

Question 14

I see a very faint star. This could mean:

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

Question 15

A neutron is made of...

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

Question 16

Which of the following is a red dwarf?

G2 V
M5 V
O4 III

Question 17

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 18

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

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

Question 19

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

A brown dwarf.
A planet.
A star.

Question 20

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

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

Question 21

Which of the following is a main-sequence star?

G2 IV
B5 II
K6 V

Question 22

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

Question 23

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

Cepheid variables
Stellar parallax
RR Lyrae variables

Question 24

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

7
8
6

Question 25

Which of the following is the longest?

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