Physical Science Domain 1 Nuclear Decay Review 1. Which nucleus would be MOST likely to be radioactive? a) C-12 b) Ca-40 c) O-16 d) Pu-241 2. An unstable nucleus emits. a) Atoms b) Electricity 3. Many of uranium are radioactive. a) Ions b) Isomers 4. Which nucleus is NOT radioactive? a) Am-241 b) Mg-24 c) Plasma d) Radiation c) Iodides d) Isotopes c) Pu-241 d) U-238 5. The nucleus of a large atom splits and two smaller atoms are formed. Energy is released in the process. What is the name of this process? a) Fusion c) Friction b) Fission d) Binary multiplication 6. Positively charged particles consisting of two protons and two neutrons emitted by radioactive materials are a) Beta particles c) Alpha particles b) Gamma particles d) Positron particles 7. Many of the technological advances over the last 50-75 years have been in the area of weaponry and warfare, such as atomic/nuclear weapons, radar, biological weapons, etc. These advances have both positive and negative aspects. Which statement describes a positive aspect of these advances? a) Biological weapons are much safer than previous weapons used. b) Because of the range of weapons these days, no place is really safe. c) Advances in equipment like radar and body armor has prevented injuries that previously couldn't have been avoided. d) The lingering radiation from atomic weapons kill people and destroy the land for a time well after the weapon is detonated. 8. Iodine-131 is a radioactive isotope that is used as a medical tracer to study and treat the thyroid gland. This radioactive element emits both beta particles and gamma waves. To effectively stop both beta particles and gamma waves, scientists use a chamber composed of a) Concrete b) Lead c) Metal d) Plastic 9. Advancements in nuclear science have led to new technology which has been beneficial to society. Which technology is a possible clean energy source for the future? a. Nuclear fusion c. Nuclear fission b. Nuclear waste d. Nuclear power rods
10. In the 18 th Century some scientists thought that the energy produced by the Sun was the result of chemical reactions. Which discovery would make this hypothesis doubtful? a) The sun is made of gas. b) Heat is absorbed or released in chemical reactions. c) Chemical reactions can take place at very high temperatures d) Energy is released when hydrogen nuclei fuse into helium nuclei 11. Which of these reactions is responsible for energy radiating from stars, including the Sun? a. Nuclear fission b. Nuclear fusion c. An exothermic chemical reaction d. An endothermic chemical reaction 12. Determine the half-life of uranium-238 based on the graph. a) 4.5 billion years b) 8 billion years c) 15 billion years d) 23 billion years 13. An Archeologist found deposits of Uranium 238 embedded in the soil from what is suspected to be an asteroid that struck earth billions of years ago. If there is only 25% of the sample remaining after years of nuclear decay, approximately how long ago did the asteroid strike earth. a) 4 billion years ago b) 8 billion years ago c) 12 billion years ago d) 16 billion years ago 14. Based on the graph to the left, determine the amount of 14 C that would remain after 17,100 years, if the original sample contained 6 grams of pure 14 C. a) 0.75 grams b) 3 grams c) 6 grams d) 1.5 grams 15. An Archeologist discovered the fossilized remains of an organism that is suspected to have lived before the dawn of man. The archeologist decides to use Carbon dating to determine the age of the fossil. If there is only 3.215% of Carbon 14 remaining in the sample, how long ago did this organism live. a) 11,400 years ago b) 17,100 years ago c) 22,800 years ago d) 28,500 years ago.
16. You start with a 500 g sample of Co-57. About how much time has passed if you end up with a 250 g sample? a) 10 days b) 20 days c) 30 days d) 40 days 17. Plutonium-241 is an isotope of plutonium that is highly radioactive and is used in some nuclear reactors and many nuclear weapons. It has a half-life of 14.4 years. If 1000g of Pu-241 is placed in storage at a weapons plant, how much will still be remaining after 28.8 years? a) 125g b) 250g c) 500g d) 1000g 18. Which form of radiation is used to directly INCREASE the temperature of water in a nuclear reactor? a) Neutrons b) Beta Particles c) Alpha Particles d) Gamma Radiation 19. What is one reason nuclear fuel is a positive alternative to fossil fuels for the creation of electrical energy? a) Nuclear power is much less hazardous than coal or oil power production. b) Nuclear power is much more widely available than coal or oil power production. c) Nuclear power produces no carbon dioxide emissions unlike coal or oil power production. d) Nuclear power does not require the use of natural resources like coal or oil power production. 20. "Spent" nuclear fuel rods come out of a reactor and need to be handled carefully. Why must power plants spend so much money and be so cautious in dealing with these materials? a) Spent nuclear fuel is very fragile and can shatter easily and damage equipment. b) Spent nuclear fuel is highly unstable, and likely to explode without precautions. c) Spent nuclear fuel is highly radioactive and can damage organisms and the environment.
d) Spent nuclear fuel is very expensive, and some people desire to take some and profit from it. 21. The source of power in a nuclear power plant comes from a) Burning hydrogen atoms. b) Reacting uranium atoms. c) Splitting uranium nuclei. d) Combining hydrogen atoms. 22. The Chernobyl accident, which occurred in the former Soviet Union in April, 1986, caused many problems. Nearly 3 million acres of farmland in the Ukraine were rendered useless for decades. Thirty-one workers died directly from the accident, while another 130 became sick. Many others in neighboring countries, like Switzerland and Poland also became sick. What type of accident was Chernobyl, considered to be one of the worst of its kind? a) Nuclear meltdown b) Act of terrorism c) Spreading wildfire d) Flooding due to torrential rains
ANSWER KEY 1) Which nucleus would be MOST likely to be radioactive? Answer: D Explanation: Pu-241 is a highly radioactive isotope. It is used in nuclear reactors and nuclear bombs because of its instability. The others have a ratio of one proton to one neutron and are very stable. 2) An unstable nucleus emits Answer: D Explanation: Radiation is an unstable nuclei's way of emitting energy to become more stable. 3) Many of uranium are radioactive. Answer: D Explanation: Isotopes are atoms of the same element with a varying number of neutrons. It is this difference in neutrons which makes some atoms more stable (and less radioactive) than others. 4) Which nuclei is NOT radioactive? Answer: B Explanation: Notice how all the other isotopes listed are big (238, 241, 241) and heavy and contain many neutrons. Usually, isotopes heavier than lead are naturally radioactive. Ordinary metals and lighter elements, like magnesium-24 are not radioactive. 5) The nucleus of a large atom splits and two smaller atoms are formed. Energy is released in the process. What is the name of this process? Answer: B Explanation: Fission is the process of nuclei breaking apart. To remember the difference between fission and fusion, remember that to fuse is to come together. In addition to smaller nuclei, fission releases energy, which drives nuclear reactors. USATestprep, Inc. 2011, All Rights Reserved
6) Positively charged particles consisting of two protons and two neutrons emitted by radioactive materials are Answer: C Explanation: Alpha particles consist of the same number of protons (2) and neutrons (2) as a helium nucleus, but they are emitted from an atom during radioactive decay. 7) Many of the technological advances over the last 50-75 years have been in the area of weaponry and warfare, such as atomic/nuclear weapons, radar, biological weapons, etc. These advances have both positive and negative aspects. Which statement describes a positive aspect of these advances? Answer: C Explanation: Advances in equipment like radar and body armor has prevented injuries that previously couldn't have been avoided. The other choices are unfortunately the negatives to the advances in weaponry. 8) Iodine-131 is a radioactive isotope that is used as a medical tracer to study and treat the thyroid gland. This radioactive element emits both beta particles and gamma waves. To effectively stop both beta particles and gamma waves, scientists use a chamber composed of Answer: B Explanation: To stop both emissions, the chamber should be made of lead. Notice the illustration. Only lead will stop gamma waves, although copper will stop beta particle penetration. USATestprep, Inc. 2011, All Rights Reserved
9) Advancements in nuclear science have led to new technology which has been beneficial to society. Which technology is a possible clean energy source for the future? Explanation: Nuclear fusion is the correct answer. Nuclear fission is what we use today in nuclear power plants, a great deal of radioactive waste, the other are by products of this process. Nuclear fusion releases a great deal of energy with a little radioactivity, but the problem is ignition temperatures; but maybe someday. 10) In the 18 th Century some scientists thought that the energy produced by the Sun was the result of chemical reactions. Which discovery would make this hypothesis doubtful? Answer: D Explanation: The discovery that Energy is released when hydrogen nuclei fuse into helium nuclei would make the hypothesis doubtful. 11) Which of these reactions is responsible for energy radiating from stars, including the Sun? Explanation: The reactions that occur in stars are nuclear fusion in which two lighter nuclei combine to give a heavier nucleus with release of enormous energy. 12)
Determine the half-life of uranium-238 based on the graph. Explanation: The half-life for U-238, based on the graph, is4.5 billion years. This is determined by going to the 50% mark on the graph and following it down to the horizontal axis. 13) Based on the graph, determine the amount of U-238 that would remain after 4.5 billion years, if the original sample contained 6 grams of pure U-238. Answer: B
Explanation: The half-life for U-238, based on the graph, is 4.5 billion years. This is determined by going to the 50% mark on the graph and following it down to the horizontal axis. So, if you start with a 6 gram sample, after 4.5 billion years, half of it would remain, or 3 grams. 14) A radioactive isotope of potassium (K) has a half-life of 20 minutes. If a 40.0 gram sample of this isotope is allowed to decay for 80 minutes, how many grams of the radioactive isotope will remain? 15) Explanation: Because it goes through 80 minutes, this is 4 half-lives, 80/20=4. During each half life, the amount is reduced by a factor of 1/2. So, it goes from 40g to 20g, 20g to 10g, 10g to 5g and finally, 5g to 2.5g. You start with a 500 g sample of Co-57. About how much time has passed if you end up with a 250 g sample? Explanation: The amount of time to break down a radioactive substance in half is known as its half-life. In 10 days, a sample of Co-57 would be reduced to half its size through decay, so a 500 g sample would decay to a 250 g sample in one half-life. 16) Plutonium-241 is an isotope of plutonium that is highly radioactive and is used in some nuclear reactors and many nuclear weapons. It has a half-life of 14.4 years. If 1000g of Pu- 241 is placed in storage at a weapons plant, how much will still be remaining after 28.8 years? Answer: B Explanation: After 14.4 years the sample will decay from 1000g to 500g, given another 14.4 years, this 500g will decay to 250g. In two half-lives, the amount will decrease by one-fourth. USATestprep, Inc. 2011, All Rights Reserved
17) Which form of radiation is used to directly INCREASE the temperature of water in a nuclear reactor? Answer: D Explanation: Gamma radiation is the highest in energy and provides most of the energy to heat up water in a nuclear reactor. This water turns to steam and turns a turbine to generate electricity. 18) What is one reason nuclear fuel is a positive alternative to fossil fuels for the creation of electrical energy? Answer: C Explanation: Nuclear power produces no carbon dioxide emissions unlike coal or oil power production. When burned, all fossil fuels produce carbon dioxide in emissions. The cloudy substance seen emitted from nuclear cooling towers is steam. 19) "Spent" nuclear fuel rods come out of a reactor and need to be handled carefully. Why must power plants spend so much money and be so cautious in dealing with these materials? Answer: C Explanation: Spent nuclear fuel is highly radioactive and can damage organisms and the environment. If the radiation leaks to the environment, it can cause mutations and even death to the surrounding ecosystem. Contrary to what some think, it is not unstable unless it is enriched to a much higher concentration. 20) The source of power in a nuclear power plant comes from Answer: C Explanation: Power in a nuclear power plant is derived from splitting uranium nuclei. This processes uses Einstein's famous E=mc 2 to produce energy from a loss of mass. This is fission. 21) The Chernobyl accident, which occurred in the former Soviet Union in April, 1986, caused many problems. Nearly 3 million acres of farmland in the Ukraine were rendered useless for decades. Thirty-one workers died directly from the accident, while another 130 became sick. Many others in neighboring countries, like Switzerland and Poland also became sick. What type of accident was Chernobyl, considered to be one of the worst of its kind? Explanation: Chernobyl is one of the worst cases of a nuclear meltdown. It was much worse than the Three Mile Island incident in 1979. Millions were exposed to large amounts of radiation, plants and animals were
killed, and farmland was rendered useless due to contamination. USATestprep, Inc. 2011, All Rights Reserved