alleryStart learning →Between uranium-235 and plutonium-239, which nuclide has the smaller critical mass?
APlutonium-239 has the smaller mass
BUranium-235 has the smaller mass
CThey have exactly the same critical mass
DNeither nuclide has a critical mass
Answer & Solution
Correct answer: A. Plutonium-239 has the smaller mass
1. Critical mass depends on how many neutrons a fission produces and how easily the nuclide undergoes fission.
2. Plutonium-239 produces more neutrons per fission than uranium-235 and is comparatively easy to fission.
3. Both factors together make the critical mass smallest for plutonium-239.
4. The two nuclides do not share the same critical mass, and both clearly do have one.
5. So plutonium-239 is correct.
_Source: OpenStax Physics (CC BY 4.0), Ch 22 "The Atom", section 22.4 Nuclear Fission and Fusion_
Keep practising The Atom
Browse all The Atom questions for Alberta Diploma Exams, or explore more Physics topics.
Related questions
The same 1.00 J of ionizing energy from the previous scenario is instead absorbed only by What is a radiopharmaceutical?What is the main obstacle that must be overcome to make two light nuclei fuse together?Fission of 1.00 kg of uranium-235 releases about 8.21 x 10^13 J, given 200 MeV per fissionAbout how much energy does the average nuclear fission reaction release?The curie (Ci) was originally defined as the activity of what quantity of radium-226?What is the SI unit for activity, defined as one decay per second?Carbon-11 has a half-life of 20.334 minutes. Starting from a 1000 g sample, about how much