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

Object A has mass 1 kg. Object B has mass 9 kg. According to E=mc², how much rest energy does object B have compared to A?

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

Question 2

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

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

Question 3

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

6
8
7

Question 4

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

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

Question 5

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

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

Question 6

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 7

What happens to the mass in electron-positron annihilation?

Its rest energy is converted into gravitational potential energy of the produced photons.
Its rest energy is converted into kinetic energy of the produced photons.
The mass is conserved, and converted into the mass of the photons.

Question 8

Which of the following is the shortest?

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

Question 9

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

Red.
Green.
Blue.

Question 10

What is nuclear fusion?

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

Question 11

Which of the following stars is the coolest?

K9
K3
K5

Question 12

Star A has brighter absolute 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 A is more luminous.
Star B is more luminous.

Question 13

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 14

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

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

Question 15

What kind of mass is defined as resistance of an object to acceleration?

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

Question 16

A star is located on the bottom right of the H-R diagram. This star has...

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

Question 17

Which of the following is a main-sequence star?

K6 V
G2 IV
B5 II

Question 18

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 star.
A brown dwarf.
A planet.

Question 19

In an atom, the protons are located...

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

Question 20

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!)

2.
1.
4.

Question 21

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

-1.
0.
+1.

Question 22

Which of the following is a red dwarf?

O4 III
G2 V
M5 V

Question 23

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 24

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?

Stellar parallax
Cepheid variables
RR Lyrae variables

Question 25

I see a very bright 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.