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 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 2

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 3

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

Question 4

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

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

Question 5

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

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

Question 6

Which of the following stars is the brightest in the sky?

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

Question 7

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

Red.
Blue.
Green.

Question 8

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 9

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 10

Which of the following stars is the coolest?

K5
K9
K3

Question 11

Which of the following is a main-sequence star?

B5 II
K6 V
G2 IV

Question 12

A proton 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 13

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

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

Question 14

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

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

Question 15

Which of the following is a blue giant?

M5 V
O4 III
M2 III

Question 16

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

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

Question 17

Which of the following is the shortest?

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

Question 18

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 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 star.
A planet.

Question 20

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

+1.
0.
-1.

Question 21

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

Question 22

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

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

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?

RR Lyrae variables
Cepheid variables
Stellar parallax

Question 24

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 25

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

6
8
7