Q1. The diagram shows a badge worn by a worker at a nuclear power station.

Transcription

1 Q1. The diagram shows a badge worn by a worker at a nuclear power station. Part of the outer black paper has been removed so that you can see the inside of the badge. Scientists examined the worker s badge at the end of a day s work. They found that the top part of the badge had been affected by radiation, but the bottom half had not. What type of radiation had the worker been exposed to? Explain the reasons for your answer (Total 2 marks) Page 1 of 31

2 Q2. The pie-chart shows the average radiation dose that a person in the UK receives each year from natural background radiation. The doses are measured in millisieverts (msv). (a) Some types of job increase the radiation dose a worker receives. People working as aircrew receive an increased radiation dose due to flying at high altitude. The radiation dose from which source of background radiation is increased by flying?... The following table gives the average additional radiation dose received by aircrew flying to various destinations from London. Destination Flight time in hours Average additional radiation dose in msv Edinburgh Istanbul Toronto Los Angeles Tokyo What is the relationship between flight time and average additional radiation dose? Page 2 of 31

3 (iii) A flight from London to Jamaica takes 10 hours. Estimate the likely value for the average additional radiation dose received by people on this flight. Average additional radiation dose =... msv Give a reason for your answer (b) The following table gives the effects of different radiation doses on the human body. Radiation dose in msv Effects Immediate illness; death within a few weeks Radiation sickness; unlikely to cause death 100 Lowest dose with evidence of causing cancer A businessman makes 10 return flights a year from London to Tokyo. Explain whether the businessman should be concerned about the additional radiation dose received during the flights. (c) In a study of 3900 aircrew it was found that 169 had developed leukaemia, a form of cancer. In a similar sized sample of non-aircrew the number of leukaemia cases was 156. Suggest why it would be difficult to be certain that the leukaemia developed by the aircrew was caused by flying. (Total 8 marks) Page 3 of 31

4 Q3. The table gives information about the three types of particle that make up an atom. Particle Relative mass Relative charge Proton +1 Neutron 1 Electron very small 1 (a) (b) (c) Complete the table by adding the two missing values. Use the information in the table to explain why an atom has no overall electrical charge. Uranium has two natural isotopes, uranium-235 and uranium-238. Uranium-235 is used as a fuel inside a nuclear reactor. Inside the reactor, atoms of uranium-235 are split and energy is released. How is the structure of an atom of uranium-235 different from the structure of an atom of uranium-238? The nucleus of a uranium-235 atom must absorb a particle before the atom is able to split. What type of particle is absorbed? (iii) The nucleus of an atom splits into smaller parts in a reactor. What name is given to this process? (Total 7 marks) Page 4 of 31

5 Q4. Radon is a radioactive element. The graph shows how the number of radon atoms in a sample of air changes with time. How long did it take the number of radon atoms in the sample of air to fall from 1000 to 500? Time =... seconds How long is the half-life of radon? Half-life =... seconds (iii) Complete this sentence by crossing out the two lines in the box that are wrong. As a radioactive material gets older, it emits less a constant level of more radiation per second. (Total 3 marks) Page 5 of 31

6 Q5. (a) The table gives information about the radioactive isotope, radon-222. mass number 222 atomic number 86 radiation emitted alpha particle Complete the following sentence. The mass number is the total number of... and... inside an atom. Radon-222 is an isotope of radon. How many protons are there in an atom of radon-222?... (iii) When an atom of radon-222 emits an alpha particle, the radon-222 changes into an atom of polonium-218. An alpha particle consists of 2 protons and 2 neutrons. How is the structure of the nucleus of a polonium-218 atom different from the structure of the nucleus of a radon-222 atom? Page 6 of 31

7 (b) The pie chart shows the average radiation dose that a person in the UK receives each year from natural background radiation. The doses are measured in millisieverts (msv). Calculate the proportion of natural background radiation that comes from radon. Show clearly how you work out your answer. Proportion of radon =... Not all background radiation is from natural sources. Name one source of background radiation that is not natural. Page 7 of 31

8 (c) The bar chart shows the average yearly dose from natural background radiation in different European countries. How many times bigger is the average annual background dose in Germany compared to the UK? The following table gives the effects of different radiation doses on the human body. Radiation dose in msv Effects Immediate illness; death within a few weeks Radiation sickness; unlikely to cause death 50 Lowest dose with evidence of causing cancer A family goes to Germany for a two-week holiday. Should they be concerned about the higher level of background radiation in Germany? Draw a ring around your answer. Yes No Explain your answer. (Total 10 marks) Page 8 of 31

9 Q6. (a) The diagrams represent three atoms X, Y and Z. X Y Z Which two of the atoms are from the same element? Give a reason for your answer. (b) In the early part of the 20 th century some scientists investigated the paths taken by positively charged alpha particles into and out of a very thin piece of gold foil. The diagram shows the paths of three alpha particles. Page 9 of 31

10 Explain the different paths A, B and C of the alpha particles. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. (3) (Total 5 marks) Q7. (a) Sam and Kris are arguing about alpha and gamma radiation. Sam says that alpha radiation is more dangerous. Kris disagrees. He thinks that gamma radiation is more dangerous. What do you think? Explain your answer as fully as you can. (4) (b) Cancer cells in a particular organ of the body can be killed by injecting a radioactive substance which is absorbed by that organ. What other features must the radioactive substance have to make it suitable for this job? Page 10 of 31

11 (c) Radon is a radioactive gas with a half-life of 3.6 days. It often seeps into buildings from the ground. Estimate how long it takes for 99% of a sample of radon gas to decay. (Show your working.) (Total 8 marks) Q8. A teacher measured the amount of radiation from a radioactive source, during the same lesson each week, over a period of six weeks. The results are shown on the graph. Page 11 of 31

12 How long does it take for the radiation to fall from 68 counts per minute to half that value? Show clearly how you work out your answer Time taken for radiation to halve... (Total 3 marks) Q9. (a) Two sources of radiation look identical. One source emits only alpha radiation, the other only beta radiation. Describe one way to find out which source emits the alpha radiation. You can assume a radiation detector and counter are available. You may wish to draw a diagram to help with your answer. (3) Page 12 of 31

13 (b) The diagram shows a beta radiation source and detector used to measure the thickness of cardboard as it is made. The table gives the detected count rate at different times. Time Count rate in counts/minute 09: : : : : Between 09:00 and 10:00 the cardboard is produced at the correct constant thickness. Give a reason for the small variation in count rate. What can you say about the thickness of the cardboard being made at 10:30? Explain the reason for your answer. (3) Page 13 of 31

14 (iii) Explain why gamma radiation is not suitable for detecting changes to the thickness of the cardboard. (Total 8 marks) Q10. In the early part of the 20th century scientists used the plum pudding model to explain the structure of the atom. (a) What did scientists think that the pudding part of the atom was? (b) The scientists Geiger and Marsden devised an experiment to test the plum pudding model. They fired positively charged alpha particles at a very thin sheet of gold foil. They then measured the different paths taken by the alpha particles. Page 14 of 31

15 List A gives some of the observations from the experiment. List B gives the conclusions reached from the observations. Draw one line from each observation in List A to the conclusion reached in List B. List A Observation List B Conclusion (c) Following the work of Geiger and Marsden, the plum pudding model of the atom was replaced by the nuclear model of the atom. Explain why it is sometimes necessary for scientists to replace a scientific model. (Total 5 marks) Q11. Most elements have some isotopes which are radioactive. (a) What is meant by the terms: isotopes radioactive? Page 15 of 31

16 (b) The graph shows how the number of nuclei in a sample of the radioactive isotope plutonium-238 changes with time. Use the graph to find the half-life of plutonium-238. Show clearly on the graph how you obtain your answer. Half-life =... years (c) The Cassini spacecraft launched in 1997 took seven years to reach Saturn. The electricity to power the instruments on board the spacecraft is generated using the heat produced from the decay of plutonium-238. Plutonium-238 decays by emitting alpha particles. What is an alpha particle? Page 16 of 31

17 During the 11 years that Cassini will orbit Saturn, the output from the generators will decrease. Explain why. (d) Plutonium-238 is highly dangerous. A tiny amount taken into the body is enough to kill a human. Plutonium-238 is unlikely to cause any harm if it is outside the body but is likely to kill if it is inside the body. Explain why. In 1964, a satellite powered by plutonium-238 was destroyed, causing the release of radioactive material into the atmosphere. Suggest why some environmental groups protested about the launch of Cassini. (Total 10 marks) Page 17 of 31

18 Q12. In the early part of the 20th century, scientists used the plum pudding model to explain the structure of the atom. Following work by Rutherford and Marsden, a new model of the atom, called the nuclear model, was suggested. (a) Describe the differences between the two models of the atom. (4) (b) In their investigation, Rutherford and Marsden fired positively charged alpha particles at a very thin sheet of gold. Over a period of several months, the scientists made over measurements. These measurements showed that: a very small number of alpha particles were deflected backwards from the gold foil. Use the nuclear model to explain this experimental result. Page 18 of 31

19 (c) Why did the work of Rutherford and Marsden convince many scientists that the plum pudding model of the atom was incorrect? (Total 8 marks) Q13. (a) Uranium-234 ( 234 U) is a radioactive element. The graph shows the number of protons and neutrons in the nuclei of the elements formed when uranium-234 decays. How does the graph show that uranium-234 ( 234 U) and thorium-230 ( 230 Th) emit alpha particles? What makes uranium and thorium different elements? (iii) Radioactive decay may also produce gamma radiation. Why does the emission of gamma radiation not cause a new element to be formed? Page 19 of 31

20 (b) The graph shows how the thickness of different materials needed to absorb 90% of the gamma radiation emitted by a source depends on the energy of the radiation. The energy of the gamma radiation is given in units called electron-volts. Which of the materials shown is least effective at absorbing gamma radiation? Use the information in the graph to give a reason for your answer. For gamma radiation of energy 1.5 million electron-volts, how many times more effective is steel than water at absorbing the radiation? Show clearly how you obtain your answer. Page 20 of 31

21 (c) Scientists in the early twentieth century thought that atoms were made up of electrons scattered inside a ball of positive charge. This was called the plum-pudding model of the atom. Plum pudding model Rutherford and Marsden did an experiment, in which a beam of alpha particles was aimed at a thin sheet of gold. Explain how the results of this experiment led to a new model of the atom. You may include one or more diagrams in your answer (3) (Total 9 marks) Page 21 of 31

22 Q14. (a) Tritium ( ) is an isotope of hydrogen. Tritium has a proton number of 1 and a mass number of 3. The diagram below shows a simple model of a tritium atom. Complete the diagram by adding the names of the particles indicated by the labels. (4) Explain how the nucleus of an ordinary hydrogen atom is different from the nucleus of a tritium atom. Ordinary hydrogen atoms ( ) have a mass number of (iii) Tritium is a radioactive substance which emits beta (β) radiation. Why do the atoms of some substances give out radiation?.. Page 22 of 31

23 (b) Tritium is one of the elements found in the waste material of the nuclear power industry. The diagram below shows a worker behind a protective screen. The container holds a mixture of different waste materials which emit alpha (α), beta (β) and gamma (γ) radiation. Suggest a suitable material for the protective screen. The material should prevent radiation from the container reaching the worker. Explain your answer (Total 10 marks) Page 23 of 31

24 Q15. (a) The graph shows how a sample of barium-143, a radioactive isotope with a short half-life, decays with time. What is meant by the term isotope? What is meant by the term half-life? (iii) Use the graph to find the half-life of barium-143. Half-life =... seconds Page 24 of 31

25 (b) Humans take in the radioactive isotope carbon-14 from their food. After their death, the proportion of carbon-14 in their bones can be used to tell how long it is since they died. Carbon-14 has a half-life of 5700 years. A bone in a living human contains 80 units of carbon-14. An identical bone taken from a skeleton found in an ancient burial ground contains 5 units of carbon-14. Calculate the age of the skeleton. Show clearly how you work out your answer. Age of skeleton =... years Why is carbon-14 unsuitable for dating a skeleton believed to be about 150 years old? (c) The increased industrial use of radioactive materials is leading to increased amounts of radioactive waste. Some people suggest that radioactive liquid waste can be mixed with water and then safely dumped at sea. Do you agree with this suggestion? Explain the reason for your answer (3) (Total 9 marks) Page 25 of 31

26 Q16. The diagram shows part of the life cycle of a star which is much bigger than the Sun. (a) What is the relationship between the masses of the dust and gas in the cloud in Stage 2 and the force of gravity between them? What is the relationship between the distance apart of the dust and gas in the cloud in Stage 2 and the force of gravity between them? Page 26 of 31

27 (b) In Stage 3 the star remains stable for millions of years. Explain why. (c) What happens in Stage 4? (Total 6 marks) Q17. (a) Explain how stars produce energy. (b) What evidence is there to suggest that the Sun was formed from the material produced when an earlier star exploded? Page 27 of 31

28 (c) It is thought that gases from the massive star Cygnus X-1 are spiralling into a black hole. Explain what is meant by the term black hole. What is produced as the gases from a star spiral into a black hole? (Total 6 marks) Q18. (a) The Sun is at the stable stage of its life. Explain, in terms of the forces acting on the Sun, what this means. (3) Page 28 of 31

29 (b) At the end of the stable stage of its life a star will change. Describe and explain the changes that could take place. (6) (Total 9 marks) Q19. Stars do not stay the same forever. (a) Over billions of years the amount of hydrogen in a star decreases. Why? (b) Describe how a massive star (at least five times bigger than the Sun) will change at the end of the main stable period. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. (4) Page 29 of 31

30 (c) The inner planets of the solar system contain atoms of the heaviest elements. Where did these atoms come from? What does this tell us about the age of the solar system compared with many of the stars in the Universe? (Total 7 marks) Q20. Describe, in as much detail as you can, the life history of a star like our Sun (Total 6 marks) Page 30 of 31

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