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Student Name: Heinemann Physics 3rd Edition Enhanced Practice Examination 1 Reading time: 15 minutes Writing time: 1 hour 30 minutes Section A – Core Areas of Study Students are to attempt ALL of the questions for BOTH areas of study. Number of questions Number of questions to be answered Number of marks 1. Nuclear physics and radioactivity 17 17 33 2. Electricity 12 12 33 Area of study Section B – Detailed Studies Students are to attempt ALL of the questions for ONE detailed study only. Detailed study Number of questions Number of questions to be answered Number of marks Astronomy OR 12 12 24 Astrophysics OR 12 12 24 Energy from the nucleus 12 12 24 Notes to students: • Write your name in the space above. • A formula sheet has been provided. • You are allowed to bring a periodic table into the exam. • Unless otherwise indicated, the diagrams in this book are not drawn to scale. • All written responses must be in English. Disclaimer: This is a practice examination. It represents Pearson Australia’s view only of what would be useful preparation material for the externally assessed examination. Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 1 Section A Instructions for Section A Answer all questions for both Areas of Study in this section in the spaces provided. Write using blue or black pen. • Where an answer box has a unit printed in it, give your answer in that unit. • In questions where more than one mark is available, appropriate working should be shown. Area of Study 1 – Nuclear physics and radioactivity Questions 1 to 6 relate to the following information. 63 28 Ni is a radioisotope of the element nickel. It is a β-particle emitter with a half-life of 100 years. Question 1 The number of protons in the nucleus of a 63 28 Ni atom is: A. 28 B. 35 C. 63 D. 91 (2 marks) Question 2 The number of neutrons in the nucleus of a 63 28 Ni atom is: A. 28 B. 35 C. 63 D. 91 (2 marks) Question 3 58 28 Ni and 63 28 Ni are both isotopes of nickel. Explain what the term isotope means. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 2 Question 4 63 28 Ni is a radioisotope of nickel. Explain what the term radioisotope means. Explain why Ni-63 is radioactive and Ni-58 is not radioactive. (2 marks) Question 5 Complete the nuclear decay equation for Ni-63 when it emits a β-particle by placing the appropriate numbers and symbols in the boxes below. 63 Ni → + β + energy 28 (2 marks) Question 6 Explain where the emitted β-particle has come from. (2 marks) Questions 7 to 11 relate to the following information. • Polonium-215 atoms decay into atoms of lead-211 by emitting an α-particle. • The average kinetic energy of the emitted α-particle is 7.39 MeV. • Polonium-215 has a half-life of 1.78 ×10−3 seconds. • 1.00 eV = 1.6 × 10 –19 J Question 7 What is the average kinetic energy of an emitted α-particle in joules? J (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 3 As an α-particle travels through air it will ionise about 100 000 atoms for every centimetre travelled. Each time an α-particle ionises an atom, the α-particle will lose about 34 eV of its kinetic energy. Question 8 Approximately how much energy would an α-particle lose as it passes through 1.0 cm of air? eV (2 marks) Question 9 Calculate the approximate distance that an α-particle with a kinetic energy of 7.39 MeV will travel in air before it loses all of its energy. Give your answer to the nearest millimetre. cm (2 marks) Question 10 –3 What percentage of the original sample of polonium-215 would be left after 4.13 × 10 seconds? (2 marks) Question 11 Along which of the paths A–C shown in Figure 1 would an α-particle emitted by a polonium-215 atom travel? + + + + + A C lead box B - - - - Figure 1 (1 mark) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 4 Questions 12 to 14 refer to the following information: On 20 August 1977 the unmanned space probe Voyager 2 (see Figure 2 below), was launched. Since its launch it has visited all four of the outer planets – Jupiter in 1979, Saturn in 1981, Uranus in 1986 and Neptune in 1989. Currently it is about 13.4 billion kilometres from the Sun and heading out of the solar system. Figure 2 To operate its electronic instruments and be able to send radio signals back to Earth, Voyager 2 was equipped with a radioisotope thermoelectric generator (RTG). RTGs use the heat generated from radioactive decay to produce electricity. The radioisotope chosen for Voyager 2’s RTG needed to: • be strongly ionising in order to release enough energy to generate the power needed by the probe’s electronic instruments and radio. • be easily shielded so that any emitted radiation would not damage the probes sensitive electronic instruments. • have a working lifetime of 35 years. To achieve this, its activity cannot drop below 40% of its initial activity. The table below is a list of five possible radioisotopes that could be used for Voyager 2’s RTG and the daughter radioisotopes resulting from their initial decay. Parent radioisotope 108 47 Ag 63 28 Ni γ β β,γ α α 720 k 70 k 510 k 5.59 M 6.13 M 418 100 30.2 88 13.1 108 47 Ag 63 29 Cu 137 56 Ba none none Energy released per decay (eV) – Half-life – Type of radiation emitted Energy released per decay (eV) Half-life (years) Daughter radioisotope Type of radiation emitted 137 55 Cs 238 94 Pu 250 98 Cf 234 92 U 246 96 Cm γ α α – 660 k 4.86 M 5.48 M – 2.6 min 2.46 × 105 years 4.70 × 103 years Question 12 Which of the five parent radioisotopes do you think would have been the most appropriate choice for use in Voyager 2’s RTG? (1 mark) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 5 Question 13 With respect to each of the three criterion provided on the previous page, suggest reasons as to why the radioisotope you chose as your answer for Question 12 is the most suitable for Voyager 2’s RTG and why the other radioisotopes are unsuitable. Where necessary you should support your answer with appropriate calculations. Ionising ability: Shielding: Working lifetime: Calculations (6 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 6 Questions 14 to 17 relate to the following information. Boron Neutron Capture Therapy (BNCT) is a specialised form of radiotherapy that provides a way of destroying the cancer cells in a tumour without injuring adjacent normal cells. The process involves injecting the patient with the non-radioactive isotope boron-10. The cancer cells in the tumour take up the boron-10 and the patient’s tumour is then irradiated with a beam of slow moving neutrons as shown in Figure 3. The slow moving neutrons are strongly absorbed by the boron-10 atoms, which will then decay by emitting α-particles with an average kinetic energy of 1.47 MeV. The daughter isotope created typically has 0.84 MeV of kinetic energy. Figure 3 Question 14 Complete the nuclear equation for the absorption of a neutron by boron-10 and its subsequent decay into an alpha particle by placing the appropriate numbers and symbols in the empty boxes below. 10 0 B + n → B → + α 5 γ + 0 (2 marks) Questions 15 to 17 relate to the following additional information. A cancer patient with a brain tumour with an estimated mass of 70.0 g was treated using BNCT. During one particular session the patient’s tumour cells received 0.50 J of radioactive energy. Question 15 Calculate the absorbed dose received by the tumour in grays. Gy (2 marks) Question 16 What would be the dose equivalent in sieverts received by the tumour if it absorbed 0.50 J of radioactive energy? Sv (1 mark) Question 17 What effect would the emitted α-particles and the daughter nuclei have on the tumour’s cells? (2 marks) End of Area of Study 1 Please turn to the next page. Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 7 Area of Study 2 – Electricity Questions 1 to 3 relate to the following information. Figure 1 shows the X-26 Taser that is used by police in the UK. A Taser is a device designed to subdue a person by making them part of an electric circuit and then sending pulses of electrical current into their body that cause uncontrolled muscle spasms. Figure 1 • When operating, the X-26 Taser sends 10 pulses of electric current into the offender each second. –4 • Each pulse of current lasts for 1.00 × 10 –3 • During each pulse 1.90 × 10 seconds. A of current flows through the offender’s body. • During each pulse the potential difference across the offender’s body at the points of contact is 350 V. Question 1 How much charge passes through the offender’s body during a single pulse from the Taser X-26? C (2 marks) Question 2 How many electrons would flow through the wires of the X-26 Taser during a single pulse? electrons (2 marks) Question 3 How much electrical energy is delivered into the offender’s body in 20 seconds? W (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 8 Questions 4 to 8 relate to the following information. As part of their studies in electricity, Paul and Natasha investigated the behaviour of two different types of conductors X and Y. The graph in Figure 2 shows the voltage and current characteristics for each of the two conductors. V (V) X Y 8.0 6.0 4.0 2.0 0 20 40 60 80 I (mA) Figure 2 Questions 4 to 6 relate to the following additional information. The students then set up the circuit shown in Figure 3. The internal resistance of the variable power supply can be ignored. The variable power supply was set so that the current flowing in the ammeter was 50 mA. A Y X Figure 3 Question 4 What was the emf supplied to the circuit shown in Figure 2? V (2 marks) Question 5 Determine the resistance of conductor X when 50 mA of current is flowing through it. Ω (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 9 Question 6 Is conductor X an example of an ohmic, or a non-ohmic conductor? Explain your answer and support it with an appropriate calculation. (3 marks) Questions 7 and 8 relate to the following additional information. The students then set up the circuit shown in Figure 4. A The variable power supply was set at 6.0 volts. X Y Figure 4 Question 7 What current now flows through the ammeter? mA (2 marks) Question 8 What power is dissipated in conductor X? W (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 10 Questions 9 and 10 relate to the circuit shown in Figure 5. 6.0 V 650 Ω 200 Ω 600 Ω Figure 5 Question 9 Show that the total resistance of the circuit in Figure 5 is 800 Ω. (3 marks) Question 10 What current flows through the 600 Ω resistor? A (3 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 11 Question 11 Figure 6 shows a diagram of a household power point. An electrician is to use an AC voltmeter to test the power point’s wiring when switched on. If the power point is wired correctly, what should each of the following readings be? Figure 6 VXY = V VXZ = V VYZ = V (2 marks) Questions 12 and 13 relate to the following information. A student wanted to investigate the differences in energy usage and running costs between two different types of light globes that emit the same amount of light. The results of her investigation are shown below. Globe 1 – Incandescent light globe Globe 2 – Compact fluorescent light (CFL) globe V = 240 volts P = 100 watts V = 240 volts P = 20 watts Average globe life = 1000 hours Purchase cost = $1.20 Average globe life = 10 000 hours Purchase cost = $5.60 Question 12 How much energy would each globe use in 1.0 hour? Globe 1 J Globe 2 J (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 12 Question 13 relates to the following additional information. Electrical energy costs $0.208 for every kWh of energy used. Question 13 Determine which of the two globes is the most economical to run. Remember to include the purchase cost of each globe in your calculations. (6 marks) End of Area of Study 2 End of Section A Please turn to the next page. Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 13 Section B Instructions for Section B Select one Detailed study. Answer all questions for the Detailed study in the spaces provided. Choose the response that is correct or that best answers the question. • A correct answer scores 2, an incorrect answer scores 0. • Marks will not be deducted for incorrect answers. • No marks will be given if more than one answer is given for any question. Detailed Study – Astronomy Question 1 Which of the following diagrams, A–D in Figure 1, best represents Tyco Brahe’s view of the universe? A B C D Figure 1 (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 14 Questions 2 to 4 relate to the following information. In 1610, Galileo used a telescope to observe the planet Jupiter. He discovered four small objects that appeared to revolve around it. He called these objects moons. Figure 2 shows diagrams of what he observed on the nights of the 7, 8, 12 and 15 January 1610. Figure 2 Question 2 As a result of his observations, Galileo concluded that: A. Larger planets had more moons than smaller planets. B. All planets have moons. C. Ptolemy’s geocentric model of the solar system was physically possible. D. Copernicus’ heliocentric model of the solar system was physically possible. (2 marks) Question 3 Which of the following ideas was proved wrong by Galileo’s observations of Jupiter? A. Many objects in space travel in circular orbits. B. All objects in space orbit Earth. C. The planets orbit the Sun. D. All planets are spheres. (2 marks) A diagram of the telescope that Galileo used to make his observations is shown below in Figure 3. The telescope’s objective lens had a diameter of 37 mm and a focal length of 980 mm. Its eyepiece had a diameter of 22 mm and a focal length of 50 mm. objective lens eyepiece Figure 3 Question 4 What was the magnification provided by Galileo’s telescope? A. 1.68 B. 0.05 C. 19.60 D. 0.05 (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 15 Question 5 relates to the following information. The International Space Station (ISS) takes 90 minutes to orbit Earth. The path of the ISS, during one orbit, is marked on the map in Figure 4 by the letter X. During the next orbit, the satellite’s path over Earth’s surface will shift due to Earth’s rotation. Figure 4 Question 5 Which of the paths, A–D, shows the satellite’s next orbit, after X? (2 marks) Question 6 Astronomers have calculated that Sirius, a star, is 8.6 light-years away from Earth. Given that the speed of light 8 is 3 × 10 ms-1 the distance in kilometres from Earth to Sirius is: 6 A. 2.58 × 10 km 9 B. 2.58 × 10 km 13 km 16 km C. 8.14 × 10 D. 8.14 × 10 (2 marks) Question 7 If a star rises at 11:00 p.m. on the 21 May, which of the times A–D, is the best estimate of the time that it will rise on the 30 May? A. midnight B. 11:00 p.m. C. 11:36 p.m. D. 10:24 p.m. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 16 Questions 8 and 9 relate to the following information. The tilt of Earth’s axis is 23.5° and the city of Melbourne’s latitude is 37.5° South. Question 8 What would be the maximum altitude reached by the Sun in the sky for an observer in Melbourne? A. 52.5° above the horizon. B. 61.0° above the horizon. C. 76.0° above the horizon. D. 90.0°, which is directly overhead. (2 marks) Question 9 At what time, and on which day, would the Sun reach its maximum altitude in the sky over Melbourne? A. local midday on the day of the spring equinox. B. local midday on the day of the summer solstice. C. local midday on the day of the autumn equinox. D. local midday on the day of the winter solstice. (2 marks) Question 10 The latitude for the city of Hobart in Tasmania is 43° South. This would mean that when viewed from Hobart the South Celestial Pole would appear to be: A. 47° above the horizon. B. 43° above the horizon. C. directly overhead. D. on the horizon. (2 marks) Question 11 The right ascension–declination coordinate system for celestial bodies equates to A. declination = latitude, RA = longitude. B. declination = longitude, RA = latitude. C. declination = altitude, RA = azimuth. D. declination = azimuth, RA = altitude. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 17 Question 12 Copernicus used the geometry of the diagram below to help him calculate the radius of Venus’s orbit. If the angle Venus-Earth-Sun = 46° and the Earth orbits the Sun at a distance of 1.00 AU, at what distance does Venus orbit the Sun? A. 0.43 AU B. 0.90 AU C. 0.69 AU D. 0.72 AU (2 marks) End of Detailed Study – Astronomy Please turn to the next page. Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 18 Detailed Study – Astrophysics Question 1 The energy released by the Sun comes mainly from: A. radioactive decay. B. exothermic chemical reactions. C. nuclear fission reactions. D. nuclear fusion reactions. (2 marks) Question 2 Based on the available evidence, astronomers believe that: A. our universe is expanding. B. our universe is in a steady state. C. our universe is contracting. D. we do not yet have sufficient evidence to determine what the universe is doing. (2 marks) Question 3 relates to the following information. In 1838 the German mathematician and astronomer Friedrich Bessel made the first recorded observations of stellar parallax. Over a six-month period Bessel measured the parallax shift (or angle) p for 61 Cygni, a star in the constellation of Cygnus the swan, to be 0.314 arc seconds. Figure 1 shows a diagram illustrating the apparent shift in 61 Cygni’s position as Earth moved from one side of its orbit to the other. Figure 1 Question 3 Based on his measurements Bessel would have calculated in parsecs, the distance to 61 Cygni, to be about: A. 0.314 pc. B. 3.14 pc. C. 3.18 pc. D. 6.36 pc. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 19 Question 4 relates to the following information. Arcturus is the third brightest star in the night sky. It is 36.7 light-years from Earth and has a measured light intensity of 5.36 × 10-8 Wm-2. Question 4 What is the luminosity of Arcturus? A. 2.47 × 10–5 W B. 9.07 × 10–4 W C. 2.35 × 1011 W D. 8.19 × 1028 W (2 marks) Question 5 relates to the following information. The diagram in Figure 2 shows the absorption spectrum for our Sun. 700 nm 600 nm 500 nm 400 nm Figure 2 Question 5 What would the absorption spectrum look like for a star that is travelling towards us and is of the same type as our Sun? A. 700 nm 600 nm 500 nm 400 nm 700 nm 600 nm 500 nm 400 nm 700 nm 600 nm 500 nm 400 nm 700 nm 600 nm 500 nm 400 nm B. C. D. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 20 Question 6 relates to the following information. Astronomers have calculated that the spiral galaxy NGC 634 shown in Figure 3 is 76.7 Mpc away from Earth. Figure 3 Question 6 How far from the Earth is NGC 634 in light-years? 7 A. 2.35 × 10 l.y. B. 2.50 × 108 l.y. C. 23.5 l.y. D. 250 l.y. (2 marks) Questions 7 to 10 relate to the Hertzsprung–Russell diagram shown in Figure 4 below. Effective Temperature (K) 25000 10000 3000 6000 -10 Absolute Magnitude, M -5 • • • • • • • • • • • • D • • • • • • • • • • • • • • • • • • ••• • •• •• • • • • • • •• •• • • •C • • • • • • • • • • • •• • • •• • • • • •• • • • • • • • • • • •A• •• • • 0 +5 • • • • • • • •• B +10 +15 O B A F G K 104 102 1 Luminosity (LStar/LSun ) • 10-2 10-4 M Spectral Class Figure 4 Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 21 Question 7 The arrows labelled B point to the central wavy line. The stars that lie along this line are referred to as members of: A. the main sequence. B. the dwarf sequence. C. the giant sequence. D. the luminosity sequence. (2 marks) Question 8 Referring to the Hertzsprung–Russell diagram shown in Figure 4 on the previous page, our Sun is currently located at: A. position A. B. position B (top arrow). C. position C. D. position D. (2 marks) Question 9 Referring to the Hertzsprung–Russell diagram shown in Figure 4 on the previous page, our Sun will move to what region after it runs out of hydrogen? A. position A. B. position B (top arrow). C. position C. D. position D. (2 marks) Question 10 Referring to the Hertzsprung–Russell diagram shown in Figure 4 on the previous page, our Sun will move to what region after it becomes a white dwarf? A. position A B. position B (bottom arrow) C. position C D. position D (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 22 Questions 11 and 12 relate to the following information. In the late 1920s, Edwin Hubble used the red shift of the light emitted by distant galaxies to calculate the speed at which they were moving away from Earth. He then plotted a graph of their speed against distance from Earth. He discovered that there was a relationship between these two variables that could be expressed in the form: v = H0d, where v = speed (km/s) and d = distance (Mpc). The currently accepted value for the constant Ho is 70 km/s/Mpc. Question 11 The distant galaxy NGC 253 is moving away from Earth at a speed of 243 km/s. How far is NGC 253 from Earth? A. 3.47 pc B. 3.47 Mpc C. 1.7 × 1044 pc D. 11.7 × 1010 km (2 marks) Question 12 What is the estimated age of the universe if Hubble’s constant is taken to be 70 km/s/Mpc? A. 1.40 × 1010 years B. 1.40 × 1013 years C. 6.88 × 1013 years D. 4.43 × 1017 years (2 marks) End of Detailed Study – Astrophysics Please turn to the next page. Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 23 Detailed Study – Energy from the nucleus Question 1 How many protons, neutrons and nucleons does an atom of 142 56 Ba have? A. 56 protons, 86 neutrons and 142 nucleons B. 86 protons, 56 neutrons and 142 nucleons C. 86 protons, 142 neutrons and 56 nucleons D. 56 protons, 142 neutrons and 86 nucleons (2 marks) Question 2 Which one of the statements A–D gives the best definition of nuclear binding energy? A. Nuclear binding energy is the energy that joins protons and neutrons together to make a nucleus. B. Nuclear binding energy is the energy needed to separate the protons and neutrons in the nucleus. C. Nuclear binding energy is the energy needed to join an atom to its electrons. D. Nuclear binding energy is the energy needed to separate all of the electrons from an atom. (2 marks) Question 3 Which one of the following equations is an example of nuclear fusion? A. 238 92 U → 234 90 Ba + 42 He + energy B. 6CO2 + 6O2 → 12O2 + C6H12O6 C. 1 1 He + 21 H → 23 He + D. 235 92 U + 01 n → 236 92 U 0 0γ → 127 50 Sn + 104 42 Ba + 5 01 n + energy (2 marks) Question 4 Which one of the statements A–D best describes the process of nuclear fission? A. Nuclear fission is the process of splitting a suitable heavier element into two lighter nuclei. B. Nuclear fission is the process in which two lighter nuclei join together to form a larger, more stable nucleus. C. Nuclear fission is the process in which radioisotopes are created. D. Nuclear fission is the process by which all radioisotopes undergo radioactive decay. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 24 Question 5 A controlled chain reaction is required to sustain nuclear fission inside a nuclear reactor. For this to occur, the number of neutrons per fission needs to be: A. equal to 0. B. equal to 1. C. greater than 1. D. less than 1. (2 marks) Question 6 The uranium that is used as fuel in nuclear reactor has been enriched so that the percentage content of U-235 is about: A. 99.3% B. 97.0% C. 3.0% D. 0.7% (2 marks) Question 7 Cadmium is often used to control the rate of nuclear fission in a reactor because cadmium atoms: A. deflect neutrons away from the fuel rods thus preventing nuclear fission. B. cause the neutrons to slow down so that they are travelling too slow to cause nuclear fission. C. cause the neutrons to speed up so that they are travelling too fast to cause nuclear fission. D. absorb neutrons thus preventing them from causing nuclear fission. (2 marks) Question 8 The role of a moderator in a nuclear reactor is to: A. absorb neutrons. B. remove excess heat energy from the reactor. C. slow down fast moving neutrons. D. stop nuclear fission from occurring. (2 marks) Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 25 Question 9 In the nuclear equation 235 92 U + 01 n → 236 92 U → 91 36 Kr + 142 86 Ba + X + energy, X is: A. 3 01 n B. 3 01 n C. 0 3n D. 3 0n (2 marks) Question 10 235 92 U + 01 n → 236 92 U → 148 57 La + 85 35 Br + 301 n + energy If the mass defect as a result of this nuclear equation is 2.12 × 10–28 kg. How much energy would be released? –11 eV –20 eV A. 1.91 × 10 B. 6.36 × 10 C. 0.40 eV D. 120 MeV (2 marks) Question 11 Which of the statements A–D best explains why fast breeder reactors do not require a moderator? A. For fission to occur, a collision with a slow-moving neutron is required. B. The neutrons released during fission are slow moving. C. The control rods slow the neutrons down so that fission can occur. D. For fission to occur, a collision with a fast-moving neutron is required. (2 marks) Question 12 One of the fusion reactions taking place in the Sun involves two helium-3 nuclei fusing together to form helium-4 and two protons. How does the mass of the reactants compare with that of the fusion products? A. The mass of the products is the same as that of the reactants because mass cannot be created or destroyed. B. The reactants have slightly more mass than the products because the binding energy for a helium-4 nucleus is greater than that of two helium-3 nuclei. C. The products have slightly more mass than the reactants because the binding energy for two helium-3 nuclei is greater than the binding energy of a helium-4 nucleus. D. The reactants have slightly more mass than the products because the total mass defect was transformed into the kinetic energy of the emitted protons. (2 marks) End of Detailed Study – Energy from the nucleus End of Section B End of Exam Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 26 Physics Practice Exam 1 – Formula Sheet Nuclear physics and radioactivity 1 absorbed dose (Gy) 2 dose equivalent 3 activity level 4 nuclear transmutation absorbed dose = E m dose equivalent = absorbed dose × quality factor A= A0 tn 1 Becquerel (Bq) = 1 nuclear transmutation per second Quality Factors γ -ray 1 β -particle 1 slow neutron fast neutron α-particle 3 10 20 1 eV = 1.6 x10-19 J Electricity 1.6 × 10-19 J 5 charge on an electron 6 electrical charge 7 electrical work 8 voltage V = IR 9 power P = VI 10 resistors in series 11 resistors in parallel Q = It W = QV RTOTAL = R1 + R2 + … + Rn 1 RTOTAL = 1 1 1 + + ... + R1 R2 Rn Astronomy 12 speed of light in a vacuum 13 speed 3.0 × 108 ms-1 v= d t Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 27 14 M= magnification f0 fe Astrophysics 15 light year 1 l.y. = 9.5 × 1015 m 16 parsec 1 pc = 3.1 × 1016 m 17 parallax 18 luminosity 19 Hubble’s Law d pc = 1 p arc sec L = b × 4πR2 v = H0 d Energy from the nucleus 20 mass-energy equation E = mc2 Prefixes/Units p = pico = 10-12 n = nano = 10-9 µ = micro = 10-6 m = milli = 10-3 k = kilo = 103 M = mega = 106 G = giga = 109 t = tonne = 103 kg End of Formula Sheet Copyright © Pearson Australia 2012 (a division of Pearson Australia Group Pty Ltd) ISBN 978 1 4425 5457 3 Page 28