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- 1. Open-ended30 seconds1 ptNaturally occurring copper has two isotopes, 63Cu and 65Cu. What is different between atoms of these two isotopes? -Nuclei of 65Cu atoms contain two more neutrons than those of 63Cu. -Nuclei of 65Cu atoms contain two less neutrons than those of 63Cu. -Nuclei of 65Cu atoms contain two more protons than those of 63Cu. -Nuclei of 65Cu atoms contain two less protons than those of 63Cu.
- 2. Open-ended30 seconds1 ptIf a nuclear reation adds an extra neutron to the nucleus of 57Fe (a stable isotope of iron), it produces 58Fe (another stable isotope of iron). Will this change in the nucleus affect the number and arrangement of the electrons in the atom that's built around this nucleus? Why or why not? -No, the number of electrons is set by the number of neutrons. -Yes, one electron will leave because of the extra neutron and the arrangement will change. -No, the number of electrons is set by the number of protons. -Yes, one electron will leave because of the extra neutron but the arrangement will not change.
- 3. Open-ended30 seconds1 ptWhen two medium-sized nuclei are stuck together during an experiment at a nuclear physics lab, the result is usually a large nucleus with too few neutrons to be stable. The nucleus soon falls apart. Why could more neutrons make it stable? -Neutrons would experience the attractive gravitational force while diluting the repulsion between electrons. -Neutrons would experience the attractive nuclear force while diluting the repulsion between electrons. -Neutrons would experience the attractive gravitational force while diluting the repulsion between protons. -Neutrons would experience the attractive nuclear force while diluting the repulsion between protons.
- 4. Open-ended30 seconds1 ptLight can't penetrate even a millimeter into plutonium, so why is a neutron able to travel centimeters into plutonium? -A neutron has no mass and only interacts with nuclei that are so small that they're hard to hit. -A neutron has no mass and doesn't interact with anything. -A neutron has no charge and only interacts with nuclei that are so small that they're hard to hit. -A neutron has no charge and doesn't interact with anything.
- 5. Open-ended30 seconds1 ptExplain the strategy of putting highly radioactive materials in a storage place for many years as a way to make them less hazardous. That wouldn't work for chemical poisons, so why does it work for radioactive materials? -With time, radioactive nuclei will exponentially decay and the materials become less and less hazardous. -With time, radioactive nuclei will linearly decay and the materials become less and less hazardous. -With time, radioactive nuclei will logarithmically decay and the materials become less and less hazardous. -All of the above choies are correct.
- 6. Open-ended30 seconds1 ptOnce fallout from a nuclear blast distributes radioactive isotopes over a region of land, why is it virtually impossible to separate many of those radioactive isotopes from the soil? -The radioactive isotopes have unstable nuclei and are chemical indistinguishable from ordinary elemental constituents of the soil. -The radioactive isotopes have stable nuclei and are chemical indistinguishable from ordinary elemental constituents of the soil. -The radioactive isotopes are chemically unstable and their nuclei are indistinguishable from ordinary elemental constituents of the soil. -None of the above choices are correct.
- 7. Open-ended30 seconds1 ptMagnetic resonance imaging isn't good at detecting bone. Why not? -MRI detects plutonium and bone contains little plutonium. -MRI detects uranium and bone contains little uranium. -MRI detects thorium and bone contains little thorium. -MRI detects hydrogen and bone contains little hydrogen.
- 8. Open-ended30 seconds1 ptA heavy thorium nucleus splits into two smaller nuclei plus a few neutrons. This is called -radioactive decay -neutron decay -nuclear fusion -nuclear fission
- 9. Open-ended30 seconds1 ptWhat is not true in a nuclear fission bomb? -The nuclei in the bomb must fission when struck by a neutron. -Each induced fission must produce more than one neutron, on average. -There must be an initial source of neutrons. -The nuclei in the bomb split into smaller and smaller pieces.
- 10. Open-ended30 seconds1 ptHow do different isotopes of an element differ? -They have different numbers of protons. -They have different numbers of atoms. -They have different numbers of neutrons. -They have different numbers of electrons.
- 11. Open-ended30 seconds1 ptA stable nuclear reactor is -subcritical. -supercritical. -at critical mass. -somewhere close to critical mass.
- 12. Open-ended30 seconds1 ptWhat happens in nuclear fusion? -A uranium nucleus fuses with a neutron to form a plutonium nucleus. -Four hydrogen nuclei combine to form a helium nucleus. -A uranium nucleus splits into small nuclei, releasing energy. -Deuterium and tritium combine to form a helium nucleus.
- 13. Open-ended30 seconds1 ptIn a typical X-ray tube, -only characteristic X-rays are produced. -both bremsstrahlung and characteristic X-rays are produced. -neither bremsstrahlung nor characteristic X-rays are produced. -only bremsstrahlung X-rays are produced.
- 14. Open-ended30 seconds1 ptWhat is true about antimatter? -It is a science fiction concept that does not really exist. -It has negative mass. -It is equally as abundant as matter in our universe. -It combines with matter, and their combined mass becomes energy.
- 15. Open-ended30 seconds1 ptA uranium nucleus has 92 protons. How many neutrons does a uranium-235 nucleus have? 92 143 235 327
- 16. Open-ended30 seconds1 ptWhich of the following is not a criterion to make a nuclear bomb? Fissionable material Excess production of neutrons Nuclear chain reaction Sufficient number of electrons to propagate the chain reaction.
- 17. Open-ended30 seconds1 ptRadioactive isotope technetium-99m has a half-life of 6 hours. What fraction of a sample of technetium-99m remains after 24 hours? ¼ 1/6 1/16 1/24
- 18. Open-ended30 seconds1 ptWhat percentage of an atom's mass is in its nucleus? -Over 99.9% -Over 99% but less than 99.9% -Over 90% but less than 99% -Less than 90%
- 19. Open-ended30 seconds1 ptWhat two Japanese cities were attacked with nuclear bombs during World War II? Tokyo and Hiroshima Hirohito and Yokohama Hiroshima and Nagasaki Tokyo and Kyoto
- 20. Open-ended30 seconds1 ptThe nuclear bombs developed during World War II used what principle? Nuclear fusion Nuclear fission Nuclear magnetic resonance Nuclear force
- 21. Open-ended30 seconds1 ptTwo different isotopes of the same element have the same number of protons and neutrons, but different numbers of electrons. same number of protons and electrons, but different numbers of neutrons. same number of neutrons, but different numbers of protons and electrons. same number of electrons, but different numbers of protons and neutrons.
- 22. Open-ended30 seconds1 ptWhat is needed for a nuclear chain reaction? Subcritical mass Critical mass Supercritical mass Infinite mass
- 23. Open-ended30 seconds1 ptWhen uranium undergoes fission, it releases an enormous amount of energy. That energy was stored in the uranium nuclei as kinetic energy in the nucleons. electrostatic potential energy - from the electrostatic forces between nucleons. gravitational potential energy - from the gravitational forces between nucleons. nuclear potential energy from the nuclear forces between nucleons.
- 24. Open-ended30 seconds1 ptWhen a free neutron collides with a uranium-235 nucleus and causes that nucleus to fission, the collision fragments contain a total of 2.5 free neutrons, on average, including the original free neutron. The critical mass for uranium-235 is about 50 kilograms. Suppose that another radioactive material, fundamentium-999, undergoes fission when struck by a neutron and the collision fragments contain a total of 0.5 neutrons, on average, including the original free neutron. What would be the critical mass of fundamentium-999? Infinite. No chain reaction could occur in fundamentium-999. About 10 kilograms. About 50 kilograms. About 250 kilograms.
- 25. Open-ended30 seconds1 ptA uranium-235 nucleus undergoes fission during a nuclear explosion. If you were to collect all the fragments of that original uranium-235 nucleus, you would find that their total combined mass is about 0.1% more than that of the original uranium-235 nucleus. less than that of the original uranium-235 nucleus. exactly the same as that of the original uranium-235 nucleus. about 1.0% more than that of the original uranium-235 nucleus.
- 26. Open-ended30 seconds1 ptUranium - 235 and Uranium - 238 should behave different chemically but the same optically. should behave similarly chemically and optically. should be different both chemically and optically. should behave similarly chemically but not optically.
- 27. Open-ended30 seconds1 ptWhat occurs whenever a charged particle accelerates? -X-ray fluorescence -Characteristic x-rays -Compton scattering -Bremsstrahlung
- 28. Open-ended30 seconds1 ptIn a common X-ray tube, electrons accelerate from the anode to cathode. cathode to anode. hot anode to anode. hot cathode to cathode.
- 29. Open-ended30 seconds1 ptAlthough most natural potassium nuclei are stable 39K (93.3%) or 41K (6.7%) nuclei, about 0.0117% are radioactive 40K nuclei, which have a half-life of 1.26 billion years. If you were worried about 40K radioactivity and wanted to wait for 95 % of the 40K in the environment to decay away, how long would you have to wait?
- 30. Open-ended30 seconds1 ptMost nuclear reactors in the United States are thermal fission reactors, reactors that slow their fission neutrons by sending those neutrons through materials known as moderators. Water is a common moderator. When a fast moving neutron enters water, it usually slows down because it drags the water molecules with it and experiences water resistance. pushes and pulls on the electrons in the water molecules and transfers most of its energy to those electrons. creates bubbles in the water as it passes and those bubbles carry away most of its energy and momentum. collides with the water nuclei and transfers most of its energy and momentum to those nuclei.
