Practice makes perfect - IB Physics Option D practice questions to try

When it comes to keeping on top of your IB studies, or preparing for your IB exams, practice is key. The more questions you answer, the more problems you work, the better you will become at understanding your subject and ascertaining what examiners are looking for in your responses. This is true of every subject, so to help you along with what many students find a particularly tricky subject, we’ve provided 15 IB Physics questions below covering Option D Astrophysics. There are 10 questions relevant to both Standard and Higher Level students and an additional five to challenge the Higher Level students among you. We’ve also supplied the answers so you can check your thinking, so don’t forget to scroll to the end to check your work.

If you find the questions helpful, be sure to check out our IB Physics Option D: Astrophysics Standard and Higher Level study guide by Hugh Duncan. The questions in this article have been extracted from this book and there are plenty more in it to keep your IB Physics Option D practice going – 50+ questions and 30+ worked examples!

10 Questions for Standard Level & Higher Level Students

1. What is the name of a gravitationally bound group of 1000 galaxies?
2. A galaxy is 6.0 x 10²² m away. How far is this in light years?
3. From what are comets made?
4. Mira has a surface temperature of 3600K. At what wavelength does the black body radiation curve peak?
5. Use red giant RG, white dwarf WD, neutron start NS, black hole BH or pulsar PU to identify the following stars: a) a strong off-axis magnetic field b) stops gravity by electron degeneracy c) likely to be a strong X ray source d) many times the diameter of the sun e) burning helium to carbon in its core f) all the electrons pushed into the nuclei of its atoms g) an escape velocity above that of light h) detected by regular flashes in the visible and radio spectrum i) of plantetary size j) this star has a surface temperature of about 3000K
6. What is Hubble’s Law?
7. M51 has a recessional velocity of 350kms^-1. If Hubble’s constant is 78 kms^-1Mpc^-1 how far away is M51 in light years?
8. Name three factors of a gas cloud that affects star formation.
9. What is inverse beta decay?
10. Would one see a type II supernova in an elliptical galaxy?

5 Additional Questions for Higher Level Students

1. What does isotropic mean?
2. Stars that are 10kpc from the centre of M31 and have a velocity of 300kms^-1. What density does this give for the galactic centre of M31? How many protons would this be equal to in cubic metre?
3. What cannot be explained by visible matter?
4. What does anisotropy in the CMB mean?
5. What is the critical density for a Hubble value of 68kms^-1Mpc^-1?

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Answers to the Physics Option D Standard & Higher Level Questions

1. Supercluster
2. 6.3 x 10⁶ ly (use 1ly = 9.46 x 10¹⁵ m)
3. Ice and dust
4. 8.1 x 10^-7
5. a) PU; b) WD; c) BH; d) RG; e) RG; f) NS; g) BH; h) PU; i) WD; j) RG
6. For a galaxy outside the local cluster recessional velocity proportional to distance
7. 14.6 Mly
8. Mass, density, radius, temperature, (mean atomic mass)
9. The capture of an electron by a proton to become a neutron
10. No

Answers to the Physics Option D Additional Higher Level Questions

1. Looks the same in all directions
2. 3.4 x 10^-21kgm^-3 which is about 200 000 protons m^-3
3. The outer velocity
4. Slight differences in the CMB temperature in different directions
5. 8.7 x 10^-27kgm^-3

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Keep Revising

The questions above are just a sample of the range of questions you will need to be practicing for your IB Physics Option D Astrophysics exam. Start practicing early and do it often so that the skills and techniques required to successfully answer questions become second nature.

Your school will have provided you with a number of great resources to help you along the way, including your IB Physics data booklet which contains all the equations you need to know. If you have more specific questions about different topic areas, check out our page featuring a number of resources for IB Physics students.