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

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

Green.
Blue.
Red.

Question 2

Which of the following is a main-sequence star?

B5 II
G2 IV
K6 V

Question 3

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 4

Which of the following stars is the coolest?

K5
K3
K9

Question 5

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

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

Question 6

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

7
8
6

Question 7

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?

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

Question 8

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

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

Question 9

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

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

Question 10

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 11

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 12

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 13

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

5 parsecs.
4 parsecs.
6 parsecs.

Question 14

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 15

Which of the following is the shortest?

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

Question 16

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 17

In an atom, the electrons are located...

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

Question 18

Which of the following is a blue giant?

M5 V
O4 III
M2 III

Question 19

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 20

A neutron is made of...

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

Question 21

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 22

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 star.
A brown dwarf.
A planet.

Question 23

In the proton-proton chain, how many total helium nuclei do we end up with?

1.
4.
2.

Question 24

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

Question 25

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

0.
+1.
-1.