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?

Blue.
Red.
Green.

Question 2

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 star.
A planet.

Question 3

In an atom, the protons are located...

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

Question 4

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?

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

Question 5

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

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

Question 6

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 7

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

6
8
7

Question 8

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 9

Which of the following is the shortest?

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

Question 10

A neutron is made of...

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

Question 11

Which of the following is a red dwarf?

O4 III
G2 V
M5 V

Question 12

Which of the following stars is the brightest 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 13

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 B is more luminous.
Star A is more luminous.

Question 14

What happens to the mass in electron-positron annihilation?

The mass is conserved, and converted into the mass of the photons.
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.

Question 15

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

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

Question 16

Which of the following stars is the coolest?

K5
K9
K3

Question 17

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

-1.
0.
+1.

Question 18

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

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

Question 19

Which of the following is a main-sequence star?

B5 II
K6 V
G2 IV

Question 20

Which is the dominant process used in a star with 2.7 solar masses to generate light?

Deuterium fusion.
The proton-proton chain.
The CNO cycle.

Question 21

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 22

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

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

Question 23

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

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

Question 24

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?

Stellar parallax
RR Lyrae variables
Cepheid variables

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!)

1.
2.
4.