Radioactivity — Paper 4 · IGCSE Sciences - Co-ordinated (Double) 0654

11 (a) A small quantity of radioactive material is taken from a nuclear reactor. Describe how a scientist could prove that the material is releasing γ-rays but not α-particles or β-particles. … … … … … [3] (b) The nuclear fuel used in a power station is plutonium-239. 239 94 Pu decays by α-emission to produce an isotope of uranium. Use the correct nuclide notation to write a symbol equation for this decay process. 239 Pu → … + … 94 [2] (c) The electricity produced in a nuclear power station is transferred from the power station to a nearby town using overhead power cables. The resistance of a length of cable may be calculated using the equation shown. length resistance = constant × cross-sectional area One length of an overhead power cable has a resistance of 7.0 Ω. Predict the resistance of a cable that has half the diameter but is the same length. resistance = … Ω [2] (d) The power station uses generators to generate electricity. Fig. 11.1 shows a simple generator. N S slip rings V Fig. 11.1 A voltage is generated when a coil of wire is turned in a magnetic field. The voltage is measured using a voltmeter connected across slip rings as shown in Fig. 11.1. (i) On the grid in Fig. 11.2, sketch a graph of voltage output against time for the generator, when the coil is rotating at constant speed. voltage output time Fig. 11.2 [2] (ii) State one way in which the size of the induced voltage can be increased. … … [1] (e) A generator is very noisy and emits sound waves which pass through the air. The speed of sound waves in air is 340 m / s. The frequency of the sound waves is 490 Hz. (i) Calculate the wavelength of the sound waves. State the formula you use and show your working. formula working wavelength = … m [2] (ii) Fig. 11.3 represents a sound wave travelling through the air from the generator. direction of travel Fig. 11.3 On Fig. 11.3, label a compression with the letter C. [1] (iii) The generator turns faster and the frequency of the sound emitted increases. Suggest how the distance between two compressions changes. … [1]

14 marks

Mark scheme: 11(a) use Geiger counter etc. ; test for absorption by shield of lead / thick aluminium ; γ-rays are more penetrating than α or β / α and β will not penetrate lead ; OR measure deflection by magnetic / electric field ; γ-rays not deflected / α and β deflected ; 3 11(b) U 235 92 ; He 4 2 OR 4 2 α ; 2 11(c) correct working ; 28 (Ω) ; 2 11(d)(i) approx sin wave ; constant amplitude ; 2 11(d)(ii) stronger magnet / spin coil faster / greater number of turns / increased coil area ; 1 11(e)(i) λ = v / f / 340 / 490 ; = 0.69 (m) ; 2 11(e)(ii) compression correctly labelled ; 1 11(e)(iii) decreases / closer together ; 1

This question in 0654/41 May/June 2017

3 (a) A list of metals is shown below. aluminium copper iron lead uranium From the list of metals choose one to match each description. Each metal can be used once, more than once or not at all. (i) It may be easily magnetised. … [1] (ii) It is used as a fuel in nuclear power stations. … [1] (iii) It is used in the core of a transformer. … [1] (b) Copper has a boiling point of 2562 °C. (i) State the meaning of the term boiling point. … … [1] (ii) When a liquid boils, energy is required but the temperature remains the same. Explain what is happening in terms of molecules. Use the term latent heat in your answer. … … … … [2] 64 (c) An isotope of copper has a nuclide notation 29 Cu and decays by the emission of β-particles to produce an isotope of zinc. Use the correct nuclide notation to write a symbol equation for this decay process. 29 Cu64 → … + … [3] (d) A block of copper has a mass of 44.8 g and a volume of 5.0 cm3. (i) Calculate the density of the block of copper. State the formula you use and show your working. formula working density = … g / cm3 [2] (ii) State the weight of the block of copper. (g = 10 N / kg) … N [1] (iii) The block of copper is resting on a desk. The area of the block in contact with the desk is 0.01 m2. Calculate the pressure exerted by the block on the desk. State the formula you use and show your working. formula working pressure = … N / m2 [2]

14 marks

Mark scheme: 3(a)(i) iron ; 1 3(a)(ii) uranium ; 1 3(a)(iii) iron ; 1 3(b)(i) temperature at which all of a liquid turns to a gas ; 1 3(b)(ii) latent heat of vapourisation ; to break bonds / to overcome attractive forces ; between the molecules / intermolecular bonds ; to increase potential energy of the molecules ; max 2 3(c) 64 30Zn ;; 0 1β − ; 3 3(d)(i) density = mass / volume or 44.8 / 5.0 ; = 8.96 (g / cm3) ; 2 3(d)(ii) 0.448 (N) ; 1 3(d)(iii) pressure = force / area or 0.448 / 0.01 ; = 44.8 (N / m2) ; 2

This question in 0654/42 May/June 2017

3 (a) A student is listening to music on her computer using headphones. (i) State the useful energy transformation that happens in the headphones. from … energy to … energy [1] (ii) Fig. 3.1 shows the heat sink on a computer chip. heat sink black metal fins computer chip Fig. 3.1 The heat sink allows unwanted thermal energy to be transferred away from the chip. Suggest two features of the heat sink that allow thermal energy to be transferred away from the chip. Explain why each feature transfers thermal energy efficiently. feature 1 … because … … feature 2 … because … … [2] (b) The student watches her teacher set up a radiation detector in the school science laboratory. A sealed radioactive source, strontium-90, is placed on the bench next to the radiation detector. Strontium-90 emits β-particles. A small count rate is measured. (i) When the teacher repeats the experiment a few minutes later, the count rate measured is slightly higher. Suggest one reason for this. … … [1] (ii) Strontium-90 decays by beta (β) emission to produce an isotope of yttrium. Use the correct nuclide notation to complete the symbol equation for this decay process. … … 9038Sr … Y + … e [3] (c) The teacher asks the student to test one of the springs from a chair. Fig. 3.2 shows the chair. spring Fig. 3.2 The student measures the extension of the spring for different stretching forces. She plots the graph shown in Fig. 3.3. 10.0 8.0 extension / mm 6.0 4.0 2.0 0 0 20 40 60 80 100 120 140 force / N Fig. 3.3 (i) The force changes the shape of the spring. State one other effect that a force can have on a body. … [1] (ii) Use Fig. 3.3 to predict the force needed to give an extension of 10.0 mm. … N [1] (iii) State the assumption you have made to make your prediction in (ii). … … … [1]

10 marks

Mark scheme: 3(a)(i) electrical to sound ; 1 3(a)(ii) lots of fins – large surface area or large surface area – more, conduction / convection / radiation / transfer, of heat / energy ; black fins – black is a good emitter of radiation ; metal fins – metal is a good conductor of heat ; max 2 3(b)(i) decay is a random process / ref to background radiation ; 1 3(b)(ii) mass number correct ; atomic number correct ; both numbers correct ; 3 3(c)(i) change in, speed / direction, of motion ; 1 Question Answer Marks 3(c)(ii) 133 N ; 1 3(c)(iii) the force needed to extend a spring is directly proportional to the extension / elastic limit not exceeded ; 1

This question in 0654/42 Oct/Nov 2017

3 (a) A radioactive isotope of iodine is used by a doctor to examine the thyroid gland of a patient. The patient takes a tablet containing the iodine, which is absorbed by the thyroid gland. The iodine emits γ-rays that are detected outside the body. Iodine-123 has a half-life of 13 hours. Suggest why the half-life of iodine-123 makes it suitable for use in the investigation of the thyroid gland. … … … [2] (b) Endoscopes are used by doctors to observe inside a patient. An endoscope uses optical fibres. (i) Complete Fig. 3.1 to show how a ray of light travels down an optical fibre by total internal reflection. Fig. 3.1 [1] (ii) Describe how light passes along optical fibres. Use the terms critical angle and total internal reflection in your answer. … … … … … [2]

5 marks

Mark scheme: 3(a) long enough to be detected in the body ; short enough for minimal risk ; 2 3(b)(i) ray of light reflects along the fibre – all angles approx. correct ; 1 3(b)(ii) no refraction / light does not escape through sides / only (total) internal reflection ; angle of incidence is greater than critical angle ; 2

This question in 0654/43 Oct/Nov 2017

9 (a) (i) The nuclear fuel used in a power station is plutonium-239. 239 94 Pu decays by α-emission to produce an isotope of uranium. Use the correct nuclide notation to write a symbol equation for this decay process. … … 239 [2] 94Pu … U + … He (ii) Explain why an α-radiation source that has been swallowed is more dangerous to humans than the same source held close to the skin outside the body. … … [1] (b) Electricity is generated in a nuclear power station by nuclear fission. Nuclear fusion occurs in the Sun to release energy. Describe the difference between nuclear fission and nuclear fusion. … … … [2] (c) There is a generator in the power station. Fig. 9.1 shows a simple electrical generator. coil N S a.c. output Fig. 9.1 Electricity is generated when the coil is turned. (i) Describe how turning the coil induces a voltage. … … [1] (ii) Explain why turning the coil induces an alternating voltage. … … [1] (iii) On the grid in Fig. 9.2, sketch a graph of voltage output against time for the generator, when the coil is rotating at constant speed. voltage output time Fig. 9.2 [2]

9 marks

Mark scheme: 9(a)(i) 239 94Pu → 235 4 92 2 U He + U nuclide ; He nuclide ; 2 9(a)(ii) unable to penetrate skin / closer to body cells when inside the body ; 1 9(b) fission is splitting of nuclei ; fusion is joining of nuclei ; 2 9(c)(i) (each side of ) coil cuts magnetic field lines / coil experiences changing magnetic field ; 1 9(c)(ii) (each side of) coil moves upwards and then downwards / changes direction ; 1 9(c)(iii) sinusoidal wave with constant time period ; equal amplitudes ; 2

This question in 0654/41 Oct/Nov 2018

9 A list of metals is shown. aluminium copper iron lead uranium (a) (i) Scientists wear protective aprons when handling radioactive materials. State which metal from the list is used in the aprons to reduce the ionising radiation passing through. … [1] 234 (ii) An isotope of uranium has a nuclide notation 92 U and decays by alpha emission to produce an isotope of thorium. Use the correct nuclide notation to write a symbol equation for this decay process. … … 23492U … Th + … He [2] (b) Fig. 9.1 shows a simplified diagram of a transformer. core output input voltage voltage 6 V secondary primary coil coil 10 turns 5 turns Fig. 9.1 (i) State which metal from the list is used in the core of a transformer. … [1] (ii) State which metal from the list is used in the coils of a transformer. … [1] (iii) Calculate the voltage induced in the secondary coil of the transformer shown in Fig. 9.1. State the formula you use and show your working. formula working output voltage = … V [2] (c) (i) A block of aluminium has a density of 2700 kg / m3. State the two quantities needed to calculate the density of the block. 1 … 2 … [1] (ii) When aluminium melts, energy is required but the temperature remains the same. Explain what is happening in terms of atoms. Use the term latent heat of fusion in your answer. … … … … … [2] (iii) Aluminium has a specific heat capacity of 913 J / (kg°C). State what is meant by this quantity. … … … [1] (iv) An aluminium cable of length 1 km has a resistance of 1.2 Ω. The cable has a cross- sectional area of 25 mm2. Determine the resistance of another aluminium cable of length 1 km that has a cross- sectional area of 50 mm2. resistance = … Ω [1]

12 marks

Mark scheme: 9(a)(i) lead ; 1 9(a)(ii) thorium correct ; helium correct ; 2 9(b)(i) iron ; 1 9(b)(ii) copper ; 1 9(b)(iii) V2 = V1 × N2 / N1 or 6 × 10 / 5 ; = 12 (V) ; 2 Question Answer Marks 9(c)(i) mass and volume ; 1 9(c)(ii) latent heat of fusion is the energy needed ; to overcome forces of attraction between particles ; 2 9(c)(iii) 913 J are / amount of energy, needed to raise the temperature of 1 kg by 1 °C ; 1 9(c)(iv) 0.6 (Ω) ; 1

This question in 0654/42 Oct/Nov 2018

6 (a) X-rays and γ-rays are both used in hospitals. They are both examples of ionising radiation. Before using an X-ray machine, the doctor moves and stands behind a lead screen. (i) Describe how X-rays are a hazard to living things. … … [1] (ii) Suggest why the screen is made of lead. … … [1] (b) (i) State, in terms of waves, the meaning of the term frequency. … … [1] (ii) The speed of all electromagnetic waves in vacuo is 3 × 108 m / s. X-rays have a wavelength of 5 nm. (1 nm = 10−9 m). Calculate the frequency of X-rays. State the formula you use and show your working. formula working frequency = … Hz [2] (c) Fig. 6.1 shows a cylinder containing oxygen used in a hospital. Fig. 6.1 (i) Describe how the oxygen molecules exert a pressure on the wall of the cylinder. … … … [2] (ii) The cylinder releases 350 dm3 of oxygen into the atmosphere at a pressure of 101 000 Pa. The volume inside the cylinder is 3.0 dm3. Calculate the pressure of the oxygen in the cylinder before the gas is released. The temperature of the oxygen does not change. State the formula you use and show your working. formula working pressure = … Pa [2] (d) Doctors use radium-223 to treat body cancers. Small quantities of radium-223 are put inside the body. Radium-223 has a half-life of 11.43 days and emits α-radiation. (i) Suggest why an α-source is used to treat cancer cells. … … [1] (ii) Suggest why radium-223 is a suitable α-source for this purpose. … … [1] 223 (iii) 88 Ra decays by α-emission to produce an isotope of radon. Use the correct nuclide notation to complete a symbol equation for this decay process. … … 223 [2] 88Ra … Rn + … He

13 marks

Mark scheme: 6(a)(i) reference to an effect of ionising radiation on body ; 1 6(a)(ii) lead absorbs X-rays / stops X-rays passing through ; 1 6(b)(i) number of oscillations per second ; 1 6(b)(ii) frequency = speed / wavelength or 3 × 108/ 5 × 10–9 ; 6 × 1016 (Hz) ; 2 6(c)(i) collide with walls / cylinder ; (collisions exert a) force on the walls / cylinder ; 2 6(c)(ii) P1 = P2 V2 / V1 or 101 000 × 350 / 3.0 ; = 12 000 000 (Pa) ; 2 6(d)(i) (alpha radiation is) ionising OR kills cells OR low penetration ; 1 6(d)(ii) half life is short / will not radiate for long (in the body) ; 1 6(d)(iii) 223 88Ra → 219 86Rn + 4 2He radon correct ; helium correct ; 2

This question in 0654/43 Oct/Nov 2018

9 (a) During a mission to the Moon in 1971, an astronaut dropped a feather and a hammer. The feather and hammer were released from the same height at the same time. Both fell for 1.3 s, and landed at the same time. The acceleration due to gravity on the Moon is 1.6 m / s2. Assume that the Moon has no atmosphere. 2.5 2.0 speed / metres per second 1.5 1.0 0.5 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 time / s Fig. 9.1 (i) On Fig. 9.1 draw the speed-time graph for the falling feather. [2] (ii) The experiment is repeated on Earth. State two differences in the results obtained. Explain your answers. difference 1 … explanation … … … difference 2 … explanation … … … [4] (b) The astronaut wears a white suit rather than a black suit. Suggest and explain a reason for this. … … … [2] (c) The astronaut is exposed to more ionising radiation than people who remain on the Earth. State one harmful effect of ionising radiation on the human body. … … [1] (d) Alpha radiation is one form of ionising radiation. 239 An isotope of plutonium, 94Pu, decays by alpha emission to produce an isotope of uranium. Use the correct nuclide notation to write a symbol equation for this decay process. 239 … + … 94Pu [2] [Total: 11]

11 marks

Mark scheme: 9(a)(i) straight line from 0,0 through 1.0, 1.6 ; stopping at t = 1.3 ; 2 9(a)(ii) hammer falls faster on Earth than on the Moon ; gravity on Earth greater ; feather falls slower on Earth than on Moon ; reference to air resistance on Earth ; hammer falls faster than feather on Earth ; reference to air resistance on Earth ; max 4 9(b) astronaut stays cooler in white / would get very hot in black ; white surfaces are better reflectors of thermal radiation (than black surfaces) / black surfaces are better absorbers of thermal radiation (than white surfaces) ; 2 9(c) cancer/mutation ; 1 9(d) ; ; 2

This question in 0654/41 May/June 2019

9 (a) Ultrasound waves are used in hospitals to scan unborn babies. Ultrasound waves have a frequency that is too high for a human to hear. (i) State, in terms of waves, what is meant by the term frequency. … … [1] (ii) Using your knowledge of the range of audible frequencies for a healthy human ear, suggest a frequency for these ultrasound waves. frequency = … Hz [1] (iii) Ultrasound waves are longitudinal waves. Describe what is meant by a longitudinal wave. … … [1] (b) Endoscopes are used by doctors in hospitals to observe the inside of a patient. An endoscope uses optical fibres. Complete Fig. 9.1 to show how a ray of light travels down an optical fibre by total internal reflection. Fig. 9.1 [2] (c) An isotope of strontium, strontium-89, is used in the treatment of bone cancer in hospitals. Strontium-89 has a half-life of 50 days. A sample of this isotope contains 4 × 1014 atoms. Some time later 3 × 1014 atoms have decayed. Calculate the time needed for this number of atoms to decay. Show your working. time = … days [3] [Total: 8]

8 marks

Mark scheme: 9(a)(i) number of waves passing a given point per unit time ; 1 9(a)(ii) frequency greater than 20 000 Hz ; 1 9(a)(iii) vibration / oscillation is in the same direction as energy transfer ; 1 9(b) total internal reflection shown ; angle correct ; 2 9(c) 1 × 1014 (atoms remain) ; indication of 2 half-lives ; (50 × 2 = ) 100 days ; 3

This question in 0654/42 May/June 2019

6 (a) Fig 6.1 shows a penguin walking on the ice in Antarctica. Fig. 6.1 The penguin has a weight of 25 N and its feet have a total area of 22 cm2. Calculate the pressure in N / m2 exerted by the penguin on the ice when it is standing on both feet. Show your working. pressure = … N / m2 [3] (b) The penguin observes a fish swimming in a pool. Fig. 6.2 shows a ray of light going from the fish to the penguin. The ray is refracted at the surface. The angles of incidence and refraction are shown. 42° 30° Fig. 6.2 Calculate the refractive index of water. Show your working. refractive index = … [2] (c) The penguin jumps into the pool of water and produces water waves. A 3-metre section of the pool is shown in Fig. 6.3. 3.0 m Fig. 6.3 (i) Show that the wavelength of the waves is 0.5 m. [1] (ii) The speed of the waves produced in the pool is 1.5 m / s. Calculate the frequency of the waves. Show your working. frequency = … Hz [2] (d) In the Antarctic, harmful ultraviolet radiation reaches the Earth’s surface. (i) State one danger to living things of being exposed to large quantities of ionising radiation. … [1] (ii) α-particles and β-particles are both types of ionising radiation. State two differences between an α-particle and a β-particle. 1 … … 2 … … [2] (iii) An isotope of an unknown element decays by β-emission to produce an isotope of silicon, which has a nucleon number of 28. Identify the unknown element and give its full nuclide notation. A periodic table is shown on page 32. … [2] [Total: 13]

13 marks

Mark scheme: 6(a) conversion of cm2 to m2 seen ; = 11 000 (N/m2) ; 3 6(b) 0.67 / 0.50 ; 1.3 ; 2 6(c)(i) 3.0 / 6.0 ; 1 6(c)(ii) f 1.5 / 0.5 ; = 3 (Hz) ; 2 6(d)(i) cancer / mutation ; 1 6(d)(ii) α particles are larger/heavier ; α particles have positive charge and β particles have negative charge ; α particles are more ionising ; α particles are less penetrating ; max 2 6(d)(iii) l 28A 13 1 mark for Al ; 1 mark for 13 and 28 in correct positions ; 2

This question in 0654/43 May/June 2019

6 (a) An iron magnet picks up two iron nails as shown in Fig. 6.1. S N Fig. 6.1 Explain why the nails do not hang vertically. … … … [2] 60 (b) An isotope of iron has a nuclide notation 26Fe and decays by beta particle emission to an isotope of cobalt. (i) State what is meant by the term isotope. … … [1] (ii) Use nuclide notation to complete the symbol equation for this β-decay process. [2] 6026Fe … + … (c) An iron wire of length 0.50 m has a cross sectional area of 4.0 × 10–5 m2 and a resistance of 1.21 × 10–3 Ω. Calculate the resistance of an iron wire of length 0.25 m that has a cross sectional area of 8.0 × 10–5 m2. resistance = … Ω [3] (d) A block of iron is on a bench. The surface of the block of iron in contact with the bench has an area of 144 cm2. The mass of the block of iron is 13.6 kg. Calculate the pressure exerted by the block of iron on the bench in N / cm2. gravitational field strength = 10 N / kg pressure = … N / cm2 [3] [Total: 11]

11 marks

Mark scheme: 6(a) ref. to induced magnetism (in) nails ; two nail heads / north poles / like poles, will repel each other ; 2 6(b)(i) atoms having same atomic number / proton number and different mass number / neutron number ; 1 6(b)(ii) 60Co ; 27 0 e ; –1 2 6(c) evidence that resistance is halved by cross sectional area change ; evidence that resistance is halved by length change ; new resistance = 3.0 × 10–4 Ω ; 3 6(d) 136 N ; pressure = force / area OR 136 / 144 ; 0.94 (N / cm2) ; 3

This question in 0654/41 Oct/Nov 2019

3 (a) Fig. 3.1 shows a bar magnet suspended by a spring above a coil that is connected to a voltmeter. spring magnet N coil S voltmeter V Fig. 3.1 When the magnet is pulled downwards into the coil and then released, it oscillates up and down inside the coil. An alternating voltage is observed on the voltmeter. Explain why an alternating voltage is observed. … … … [2] (b) A thin piece of iron wire has a diameter of 0.20 mm. (i) Name the device which could accurately measure very small distances such as 0.20 mm. … [1] (ii) The wire is 0.10 m in length and has a resistance of 0.30 Ω. Determine the resistance of a piece of wire made from the same iron metal that is 0.10 m in length but has a diameter of 0.40 mm. resistance = … Ω [2] (c) The isotope iron-55 has a half-life of 2.7 years. A sample of this isotope contains 8 × 1012 atoms. Some time later 7 × 1012 atoms have decayed. Calculate the time needed for this number of atoms to decay. time = … years [3] (d) Fig. 3.2 shows an iron rod being heated at one end by a Bunsen burner. Fig. 3.2 Thermal energy passes through the rod by conduction. (i) Describe the process of conduction in solid iron, using ideas about the vibration of atoms. … … … … [2] (ii) When heated, the iron rod expands. Explain in terms of the motion and arrangement of the atoms why iron expands when heated. … … … [2] [Total: 12]

12 marks

Mark scheme: 3(a) voltage induced as coil cuts magnetic field / induced as magnetic field in coil changes ; voltage reverses when magnet changes direction ; 2 3(b)(i) micrometer screw gauge ; 1 3(b)(ii) doubling diameter quadruples CSA / evidence of dividing by 4 ; 0.075 (Ω) ; 2 3(c) 1 × 1012 atoms undecayed ; 3 half-lives ; (3 × 2.7) = 8.1 (years) ; 3 3(d)(i) (incident energy / energy gained, makes) atoms vibrate more ; this vibration is passed through metal ; 2 3(d)(ii) atoms have greater (amplitude of) vibration ; about a fixed point so take up more space / (average) distance between particles increases / owtte ; 2

This question in 0654/43 Oct/Nov 2019

9 (a) Visible light and γ-radiation are both used in hospitals. They are both examples of electromagnetic waves. γ-radiation travels at a speed of 3.0 × 108 m / s in a vacuum. (i) State the speed at which visible light travels in a vacuum. speed = … m / s [1] (ii) γ-radiation has a wavelength of 8 × 10–12 m. Calculate the frequency of γ-radiation. State the unit of your answer. frequency = … unit … [3] (b) Doctors use visible light and optical fibres to see inside the human body. Visible light passes along optical fibres by total internal reflection. (i) Fig. 9.1 shows a ray of light passing into an optical fibre. On Fig. 9.1 continue the ray of light to show its path through the optical fibre. light ray optical fibre Fig. 9.1 [1] (ii) Explain why total internal reflection occurs. … … [1] (c) Doctors use an isotope of iodine, I-123, to examine the thyroid gland of a patient. Small quantities of I-123 are absorbed by the thyroid gland. I-123 emits γ-radiation which is detected outside the body. I-123 has a half-life of 13 hours. (i) Give two reasons why I-123 is suitable for use inside the body. 1 … … 2 … … [2] (ii) A sample of I-123 contains 8 × 1014 atoms. Sometime later 6 × 1014 atoms have decayed. Calculate the time needed for this number of atoms to decay. time = … hours [2] [Total: 10]

10 marks

Mark scheme: 9(a)(i) 3 × 108 m/s; 9(a)(ii) v = frequency × wavelength or correct substitution; 3.75 × 1019 ; Hz; 3 9(b)(i) angles approximately correct for at least two reflections; 1 9(b)(ii) angle of incidence exceeds critical angle; 1 9(c)(i) relatively short half-life; γ-radiation can pass through body cells and be detected outside the body; γ-radiation is the least ionising; max 2 9(c)(ii) two half-lives (have occurred); 26 (hours); 2

This question in 0654/41 May/June 2020

6 The nuclear fuel used in some power stations is plutonium-239. (a) (i) Plutonium-239 decays by α-particle emission. Use nuclide notation to complete the symbol equation for this decay process. 23994Pu [3] (ii) Plutonium-239 has a half-life of 24 000 years. 2 kg of plutonium-239 is sealed in a lead container. Calculate the mass of plutonium-239 remaining after 120 000 years. mass = … kg [2] (b) The nuclear fuel releases 8.6 × 1013 J of energy. From this, only 3.2 × 1013 J of electrical energy is generated. Calculate the efficiency of this generation process. efficiency = … % [2] (c) The power station generates electricity at 25 000 V. A transformer increases this voltage to 400 000 V before the electricity is transmitted over large distances through transmission cables. The number of turns on the secondary coil of the transformer is 500 000. Calculate the number of turns on the primary coil of the transformer. number of turns = … [2] (d) When electricity has been generated at the power station the voltage is increased by a transformer to reduce power losses in the transmission cables. Explain why power losses in cables are lower when the voltage is high. … … … … [2] [Total: 11]

11 marks

Mark scheme: 6(a)(i) uranium identified; 235 and 92; helium notation correct; 3 6(a)(ii) five half-lives; 0.0625 (kg); 2 6(b) formula or correct substitution; 37(%) 2 6(c) V1/V2 = N1/N2 or correct substitution; 62 500 ; 2 6(d) higher voltage means lower current; power loss increases with current / power loss is I2R; 2

This question in 0654/42 May/June 2020

9 (a) A student cycles to school. Fig. 9.1 shows a speed–time graph for the journey. 8 speed 7 m / s 6 5 4 3 2 1 0 0 5 10 15 20 25 30 time / s Fig. 9.1 (i) Draw an X on Fig. 9.1 to identify the part of the journey where there is maximum acceleration. [1] (ii) Calculate the acceleration of the student and bicycle at time = 5 s. acceleration = … m / s2 [2] (b) At school, the student is asked how she would accurately measure the width of one of the brake cables on her bicycle. Name a measuring device suitable for measuring very small distances accurately. … [1] (c) The student watches her teacher set up an experiment to detect the β‑radiation emitted by a radioactive source, strontium‑90 (Sr). When strontium‑90 decays it produces an isotope of yttrium (Y). (i) Use the correct nuclide notation to complete the symbol equation for this decay process. 90 … … Sr Y + β … … … [3] (ii) State one difference between the behaviour of β‑particles and γ‑rays in an electric field. … … [1] [Total: 8]

8 marks

Mark scheme: 9(a)(i) X between t > 15 s and t < 16.8 s ; 1 9(a)(ii) change in speed or 5.0 or gradient calculation ; time taken 7.0 0.7 (m / s2) ; 2 9(b) micrometer screw gauge ; 1 9(c)(i) − → β 90 90 0 38 39 1 Sr Y+ strontium notation correct ; yttrium notation correct ; beta notation correct ; 3 9(c)(ii) β-particles deflected / gamma rays are not deflected ; 1

This question in 0654/41 Oct/Nov 2020

6 (a) A horse of mass 450 kg accelerates constantly from rest and reaches a maximum speed of 9 m /s after 3 seconds. In this time, the horse has travelled 13.5 m. (i) Show that the force that causes the acceleration of the horse is 1350 N. [3] (ii) Calculate the work done by the horse in travelling 13.5 m. work done = … J [2] (b) The horse stands with all four hooves in contact with the ground. The horse exerts a force of 4500 N on the ground. Each hoof of the horse has an area of 90 cm2. Calculate the pressure, in N / m2, exerted by the horse on the ground. pressure = … N / m2 [3] (c) Horseshoes are usually made from either iron or steel. Describe one difference between the magnetic properties of iron and steel. … … [1] (d) The audible frequency range for horses is from 14 Hz to 25 000 Hz. Compare this range to that of a human. … … [1] (e) A horse is treated for cancer using the isotope iridium-192. The iridium-192 is injected into the cancer. Iridium-192 decays by β-emission to produce an isotope of platinum. Use nuclide notation to complete the symbol equation for the β-decay process. 192 … … lr Pt + β [2] 77 … … [Total: 12]

12 marks

Mark scheme: 6(a)(i) acceleration = 9/3 = 3 m/s2 ; force = mass × acceleration ; working or 3 × 450 (= 1350 N) ; 6(a)(ii) work done = force × distance / 1350 × 13.5 ; = 18 200 (J) ; 2 6(b) 90 × 4 = 360 (cm2) = 0.036 m2 ; pressure = force / area or 4500 / 0.036 ; pressure = 125 000 (N/m2) ; 3 6(c) iron, magnetises / loses magnetism, quicker ; steel, magnetises / loses magnetism, slower ; max 1 1 6(d) humans have smaller audible range ; 1 6(e) − → + β 192 192 0 77 78 1 r Pt I ;; 2

This question in 0654/42 Oct/Nov 2020

12 (a) Fig. 12.1 shows a hot water storage tank in a house. hot water outlet tank water electric cold water heater inlet Fig. 12.1 The water is heated by an electric heater placed near the bottom of the tank. Cold water enters at the bottom of the tank and hot water leaves at the top of the tank. Explain why all the water in the tank is heated by convection. … … … … [3] (b) The house is fitted with a smoke detector. The smoke detector contains a radioactive isotope of americium-241. Americium-241 decays by α-particle emission. (i) Explain why it is safe to use this isotope of americium near people in the house. … … [1] (ii) Use nuclide notation to complete the symbol equation for the α-decay process. 241 … … Am Np + … 95 … … [4] (c) There is a rechargeable electric toothbrush in the bathroom of the house. Fig. 12.2 shows the electric toothbrush and the charger. Fig. 12.2 In the charger, there is a transformer that steps down the voltage from 220 V to 2.4 V. The primary coil of the transformer has 5000 turns. Calculate the number of turns on the secondary coil. number of turns = … [2] [Total: 10]

10 marks

Mark scheme: 12(a) hot water is less dense / expands ; less dense water rises ORA ; cold water sinks ; 3 12(b)(i) alpha particles have low penetration; 1 12(b)(ii) 241 95 Au → + 237 4 93 2 He Np mass numbers and proton numbers correct: 237 ; 93 ; 4 ; 2He ; 4 12(c) (NS =) NPVS / VP or 5000 x 2.4 / 220 ; 54.5 / 54 / 55 turns; 2

This question in 0654/43 Oct/Nov 2020

6 Strontium‑90 (90Sr) is a radioactive isotope. (a) Strontium‑90 decays by beta emission to form an isotope of yttrium and a β‑particle. (i) State the nature of a β‑particle. … [1] (ii) Use the correct nuclide notation to complete the symbol equation for this decay process. 90 … 0 38 Sr … Y + –1 β [2] (b) Fig. 6.1 shows how this isotope of strontium can be used in a paper mill to determine the thickness of paper passing through a set of rollers. beta particle movable source rollers paper detector automatic roller counter controllers Fig. 6.1 Describe and explain what happens to the reading on the automatic counter if the paper becomes thicker. … … … … … [2] (c) Table 6.1 shows how the activity of a strontium source varies over a 60‑year period. Table 6.1 age of source activity of source / years / counts per minute 0 2000 15 1400 30 1000 45 700 60 500 (i) Use Table 6.1 to determine the half‑life of strontium‑90. … [1] (ii) Suggest why this half‑life makes it suitable for use in a paper mill. … … [1] [Total: 7]

7 marks

Mark scheme: 6(a)(i) electron ; 1 6(a)(ii) 90 39Y ;; 2 6(b) reading would decrease ; fewer beta particles would penetrate paper / more absorbed ; 2 6(c)(i) 30 (years) ; 1 6(c)(ii) does not need replacing regularly / activity will remain high for a long time ; 1

This question in 0654/41 May/June 2021

9 Nuclear power stations use uranium as a fuel. (a) Name the process which releases energy from uranium in nuclear power stations. … [1] (b) Uranium-238 is unstable and decays to produce an isotope of thorium. Use the correct nuclide notation to complete the symbol equation for this decay process. 238 234 … 92 U … Th + … … [2] (c) The isotope of thorium produced is also unstable and decays releasing more ionising radiation. Fig. 9.1 shows how the activity of a sample of thorium-234 varies over time. 120 100 80 count rate / arbitrary units 60 40 20 0 0 50 100 150 200 250 time / days Fig. 9.1 Use Fig. 9.1 to calculate the half-life of thorium-234. half-life = … [2] (d) Fig. 9.2 shows radioactive emissions passing between two oppositely charged plates. charged plate + + + + + + + + + + + + + + + α β γ charged plate – – – – – – – – – – – – – – – Fig. 9.2 (i) An electric field exists between the charged plates. Describe what is meant by an electric field. … … [1] (ii) Complete Fig. 9.2 to show the paths of an α-particle, a β-particle and a γ-ray as they pass through the electric field. [3] [Total: 9]

9 marks

Mark scheme: 9(a) (nuclear) fission ; 1 9(b) 238 92U  234 90Th + 4 2α ;; 2 9(c) 25 ; days ; 2 9(d)(i) a region in which an electric charge experience a force ; 1 Question Answer Marks 9(d)(ii) ;;; 3

This question in 0654/42 May/June 2021

3 Carbon-14 is an unstable isotope which decays to produce nitrogen -14. (a) State what is meant by an isotope. … … [1] (b) Use the correct nuclide notation to complete the symbol equation for this decay process. 14 __ __ __ 6C __ N + __ [2] (c) Fig. 3.1 shows the percentage of carbon-14 in a sample. 100 90 80 % carbon-14 atoms remaining 70 60 50 40 30 20 10 0 0 10 000 20 000 30 000 40 000 50 000 age of sample / years Fig. 3.1 Use Fig. 3.1 to determine the half-life of carbon-14. half-life = … years [2] (d) The decay of unstable isotopes can also release gamma rays which are part of the electromagnetic spectrum. (i) On Fig. 3.2 write gamma in the correct position. visible infrared microwaves Fig. 3.2 [1] (ii) State the speed of the gamma rays produced by radioactive decay. … [1] (iii) A gamma ray has a wavelength of 2.0 × 10–11 m. Use your answer to (d)(ii) to calculate the frequency of this gamma ray. State the unit for your answer. frequency = … unit … [3] (iv) Draw lines to match each form of electromagnetic radiation to its use. form of electromagnetic uses radiation infrared medicine and security microwaves radio and TV communications radiowaves remote controls and intruder alarms X-rays satellite television and telephones [2] (e) All electromagnetic waves are transverse waves. Sound is an example of a longitudinal wave. Give one difference between transverse and longitudinal waves. … … [1] [Total: 13]

13 marks

Mark scheme: 3(a) same proton number and different neutron number ; 1 3(b) 14 7N ; 0 1β − ; 2 3(c) use of graph ; 6000 years ; 2 3(d)(i) gamma in left box ; 1 3(d)(ii) 3 × 108 m / s ; 1 3(d)(iii) (f=) v / λ or 3x108 / 2.0x10-11 ; 1.5 x 1019 ; Hz ; 3 3(d)(iv) ;; 2 3(e) transverse vibrations are perpendicular to energy transfer / longitudinal vibrations are parallel to energy transfer ; 1

This question in 0654/43 Oct/Nov 2021

12 (a) Fig. 12.1 shows an incomplete electromagnetic spectrum. radio visible P Q R X-rays γ-rays waves light Fig. 12.1 State the names of the forms of radiation labelled P, Q and R. P … Q … R … [2] (b) Visible light can be used to demonstrate refraction. Fig. 12.2 shows refraction of visible light through a glass block. 30° 15° 15° 30° Fig. 12.2 Calculate the refractive index of the glass block. refractive index = … [2] (c) γ-rays are a form of ionising radiation emitted during radioactive decay. (i) Draw lines to match each form of ionising radiation with its nature and relative ionising effect. One line has been drawn as an example. form of relative ionising nature ionising radiation effect electromagnetic α-particle high radiation β-particle electron medium γ-ray helium nucleus low [2] (ii) Lead-210 ( 21082 Pb) will decay to form an isotope of bismuth. Use the correct nuclide notation to complete the decay equation for lead-210. 210 Pb … Bi + … … 82 83 … [2] (iii) Fig. 12.3 shows the activity of a sample of lead-210. 400 300 activity 200counts / min 100 0 0 20 40 60 80 100 time / years Fig. 12.3 Use Fig. 12.3 to determine the half-life of lead-210. half-life = … years [2] [Total: 10]

10 marks

Mark scheme: 12(a) microwaves infrared ultraviolet ;; 2 12(b) (n =) sin i / sin r or sin 30 / sin 15 ; (n =) 1.93 ; 2 12(c)(i) ;; 2 Question Answer Marks 12(c)(ii) ;; 2 12(c)(iii) identification of 190 counts per min / correct working on graph ; 22 (years) ; 2

This question in 0654/42 Feb/March 2022

12 (a) Fig. 12.1 shows a transformer. a.c. power supply V Fig. 12.1 (i) On Fig. 12.1, label the soft‑iron core with an X. [1] (ii) The transformer has 17 turns on the primary coil and 8 turns on the secondary coil. Calculate the output voltage when the a.c. power supply has an e.m.f. of 34 000 V. Assume the transformer has an efficiency of 100%. output voltage = … V [2] (b) Fig. 12.2 shows a current‑carrying solenoid. I I Fig. 12.2 On Fig. 12.2, draw the magnetic field pattern, including direction, around the solenoid. [2] (c) The radioactive isotope uranium‑238 decays into an isotope of thorium by emitting an α‑particle. (i) Use the correct nuclide notation to complete the decay equation for uranium‑238. 238 … … 92 U … Th + … α [2] (ii) Suggest why an α‑particle is deflected when moving through a magnetic field. … … … … [2] [Total: 9]

9 marks

Mark scheme: 12(a)(i) soft-iron core correctly labelled ; 1 12(a)(ii) use of Vp / Vs =Np / Ns ; 16 000 (V) ; 2 12(b) ;; 2 12(c)(i) ;; 2 Question Answer Marks 12(c)(ii) (alpha particle is) charged ; so experiences a force ; 2

This question in 0654/42 May/June 2022

12 Fig. 12.1 shows a forklift truck lifting a crate. crate height = 2.2 m Fig. 12.1 (a) The forklift truck does 2750 J of work on the crate when the crate is lifted through a height of 2.2 m. The gravitational field strength, g, is 10 N / kg. Calculate the mass of the crate. mass = … kg [2] (b) Fig. 12.2 shows the same forklift truck after it has lowered the crate. crate Fig. 12.2 Explain why the forklift truck is more stable after it has lowered the crate. Use ideas about centre of mass in your answer. … … [1] (c) The forklift truck uses an electric motor to lift the crate. Fig. 12.3 shows a simple d.c. motor. coil Y N X Z S – + Fig. 12.3 (i) A current flows through the coil. Draw arrows on Fig. 12.3 to show the direction of the force acting on points X and Z on the coil. [1] (ii) State why point Y does not experience a force. … … [1] (d) A β-particle passes between the poles of a permanent magnet. (i) Suggest why a β-particle is deflected when moving through a magnetic field. … … … … [2] (ii) State and explain how the deflection direction of an α-particle would differ from that of the β-particle. … … … … [2]

9 marks

Mark scheme: 12(a) (m =) W / gh OR  2750 10 2.2 ; 125 (kg) ; 2 12(b) lower centre of mass ; 1 12(c)(i) X arrow pointing up AND Z arrow pointing down ; 1 12(c)(ii) the current is parallel to the magnetic field ; 1 12(d)(i) experiences a force ; it is a charged particle ; 2 Question Answer Marks 12(d)(ii) opposite direction ; because the charge is opposite /  is positive and  is negative ; OR less deflection ; due to (much) larger mass ; max 2 2

This question in 0654/43 May/June 2022

12 α-particles, β-particles and γ-rays are all forms of ionising radiation. (a) State one effect of ionising radiation on living things. … [1] (b) The radioactive isotope uranium-238 decays into the isotope thorium-234 by emitting an α-particle. Use the correct nuclide notation to complete the decay equation for uranium-238. … 238 234 … α [2] 92U … Th + (c) Gamma radiation is part of the electromagnetic spectrum. (i) State the speed of gamma radiation in a vacuum. … [1] (ii) Draw lines to match each form of electromagnetic radiation to its use. One line has been drawn for you. form of electromagnetic use radiation infrared medicine and security radio and TV microwaves communications remote controls and radio waves intruder alarms satellite television and X-rays telephones [2] (d) Visible light is also part of the electromagnetic spectrum. Fig. 12.1 shows an object emitting visible light and a thin converging lens. object F F F = principal focus Fig. 12.1 (i) Complete Fig. 12.1 to show how the rays of light from the object form an image. [3] (ii) The image formed is a real image. State one difference between a real image and a virtual image. … … [1] [Total: 10]

10 marks

Mark scheme: 12(a) cancer ; 1 12(b) 2 ; 12(c)(i) 3  108 m / s ; 1 12(c)(ii) 2 ;; 1 correct = 0 2 or 3 correct = 1 4 correct = 2 12(d)(i) 3 any 2 rays ; image ; 12(d)(i)(i) any one from: 1 real image can be projected on to a screen / ora ; real image is formed where rays of light actually converge / ora ;

This question in 0654/41 Oct/Nov 2022

12 Fig. 12.1 shows the equipment used by a teacher to demonstrate the properties of ionising radiation. The teacher uses a source which emits α-particles and a thick lead shield placed between the radioactive source and the radiation detector. radiation detector counter 019 thick lead shield source emitting α-particles Fig. 12.1 (a) (i) Explain why the count rate recorded by the laptop is low but not zero. … … … … [2] (ii) The teacher replaces the source emitting α-particles with a source that emits γ-rays. The count rate recorded by the laptop increases. Suggest why the count rate recorded by the laptop increases. … … [1] (b) Before performing the investigation, the teacher uses a plane mirror to inspect the condition of the radioactive source. (i) Complete Fig. 12.2, with a ray diagram, to show how the mirror allows the teacher to see the radioactive source. eye radioactive source mirror Fig. 12.2 [2] (ii) Visible light is an example of a transverse wave. State what is meant by a transverse wave. … … … [2] (iii) A visible light wave travels at 3.0 × 108 m / s and has a frequency of 5.0 × 1014 Hz. Calculate the wavelength of the visible light wave. wavelength = … m [2] [Total: 9]

9 marks

Mark scheme: 12(a)(i) α-particles cannot penetrate the lead ; 2 (only recording) background radiation ; 12(a)(ii) gamma is more penetrating (than alpha) ; 1 12(b)(i) 2 correct angle of reflection ; correct arrow direction ; 12(b)(ii) (transfers energy through) oscillations / vibrations ; 2 oscillations are perpendicular to direction of energy transfer ; 12(b)(iii) (λ =) v / f or 3.0  108/5.0  1014 ; 2 (λ =) 6.0  10-7 (m) ;

This question in 0654/42 Oct/Nov 2022

9 Fig. 9.1 shows the equipment used by a teacher to demonstrate the properties of ionising radiation to a group of students. They are using a source which emits β-particles. radiation detector counter 019 source emitting β-particles Fig. 9.1 (a) The radioactive source can be moved further away from the radiation detector. The teacher measures the distance between the source and the radiation detector and records the count rate using the laptop. Fig. 9.2 shows the results plotted as a graph. 200 150 counts per minute 100 50 0 0 10 20 30 40 50 distance / cm Fig. 9.2 (i) Describe the trend shown in Fig. 9.2. … … … … [2] (ii) Use Fig. 9.2 to explain why the teacher tells the students to stand at least 2 m away from the radioactive source for their own safety. … … … … [2] (iii) The teacher replaces the radioactive source with one which only emits α-particles. The source which only emits α-particles also measures a count rate of 200 per minute at a distance of 0 m. On Fig. 9.2, draw a line to show the results the teacher obtains when using the source which emits only α-particles. [2] (b) Fig. 9.3 shows the information sticker on the laptop. power input = 65 W potential difference = 19.5 V Fig. 9.3 (i) The laptop has an efficiency of 80%. Calculate the useful power output of the laptop. power = … W [2] (ii) Power for the laptop comes from a 230 V supply through a device in the charger which changes the potential difference to 19.5 V. State the name of this device. … [1] [Total: 9]

9 marks

Mark scheme: 9(a)(i) as distance increases, count rate decreases ; 2 largest decrease at shortest distances / owtte ; 9(a)(ii) beta particles, are ionising/can cause cancer/damages cells/damages DNA or genetic material ; 2 beta particles travel less than 2 m in air / count rate at 2 m is (almost) zero / very few (beta particles) after 50 cm ; 9(a)(iii) correct shape starting at 200 counts per min ; 2 (curve) drawn lower than beta ; 9(b)(i) (power output =) 65  0.8 ; 2 52 (W) ; 9(b)(ii) (step-down) transformer ; 1

This question in 0654/43 Oct/Nov 2022

12 Fig. 12.1 shows a wire being moved between the poles of a magnet. The wire is connected to an ammeter which measures the current induced in the wire as the wire is moved. When the wire moves from left to right the ammeter shows a positive reading. movement of wire S A N Fig. 12.1 (a) (i) Explain why a current is induced in the wire as it is moved between the poles of the magnet. … … … … [2] (ii) Place ticks (3) in Table 12.1 to show how the reading on the ammeter changes under different conditions. Table 12.1 ammeter reading the wire in (a)(i) is: becomes zero increases decreases becomes negative moved faster moved from right to left kept stationary replaced with a wire of lower resistance [2] (b) A magnet is used to investigate the behaviour of ionising radiation. (i) Fig. 12.2 shows the paths taken by three types of ionising radiation as they pass through a magnetic field. alpha S P Q N Fig. 12.2 The path taken by an alpha particle has been labelled for you. State the types of radiation which would follow the paths labelled P and Q. P … Q … [1] (ii) When americium‑241 (24195 Am) decays it emits an alpha particle. Use the correct nuclide notation to complete the decay equation for americium‑241. 241 Am … Np + … α 95 93 … [2] (iii) Americium‑241 is a source of alpha particles. It is used in smoke detectors. Fig. 12.3 shows part of the inside of a smoke detector. The alpha particles cause a current in the sensor. When the detector fills with smoke, a change in current is detected by a sensor which sounds an alarm. alarm circuit source of alpha particles Am sensor path of alpha particles lead shield Fig. 12.3 Suggest two reasons why a source of alpha particles is used and not any other type of ionising radiation. 1 … … 2 … … [2] [Total: 9]

9 marks

Mark scheme: 12(a)(i) the wire experiences a changing magnetic field ; 2 an emf is induced in the wire ; 12(a)(ii) 2 ammeter reading the wire in (a)(i) is: becomes zero increases decreases becomes negative moved faster ✓ moved right to left ✓ kept stationary ✓ replaced with a wire with a lower ✓ resistance ;; 12(b)(i) (P:) beta AND 1 (Q:) gamma ; 12(b)(ii) 2 ;; 12(b)(iii) least penetrating / short range ; 2 easily stopped by smoke ; AVP ;

This question in 0654/42 Feb/March 2023

12 A student investigates the penetrating abilities of ionising radiation. Fig. 12.1 shows the equipment used by the student. source of ionising counter radiation detector shielding material Fig. 12.1 (a) The student places different shielding materials between the source and the detector and uses the counter to record the number of counts in 1 minute. Table 12.1 shows the student’s results. Table 12.1 shielding material counts in 1 minute no material (air only) 2560 paper 2555 thin aluminium 23 thick aluminium 24 thin lead 22 thick lead 17 (i) Use Table 12.1 to state and explain which type of ionising radiation is emitted by the source. type of ionising radiation … explanation … … … … … [3] (ii) The source used in Fig. 12.1 has a half‑life of 29 years. Calculate the time it will take for the activity of the source to drop to 12.5% of the original value. time = … years [2] (b) The lead used in the student’s investigation is a solid. The melting point of lead is 327 °C. When lead melts, it turns from a solid into a liquid. Describe the changes in the forces between particles when a solid melts. … … [1] (c) The density of liquid lead is 10.6 g / cm3. A sample of liquid lead has a mass of 37.1 g. Calculate the volume of the sample of liquid lead. volume = … cm3 [2] [Total: 8]

8 marks

Mark scheme: 12(a)(i) beta ; (beta) can penetrate (air and) paper ; (beta) can’t penetrate thin aluminium (and thicker materials) ; 3 12(a)(ii) 3 half lives ; (t = 3  29 =) 87 (years) ; 2 12(b) (forces between particles) decrease ; 1 12(c) d = m / v or v = m / d or v = 37.1 / 10.6 ; = 3.5 (cm3) ; 2

This question in 0654/41 May/June 2023

12 (a) Table 12.1 shows information about three types of ionising radiation. Table 12.1 type of ionising relative nature of radiation relative penetrating ability radiation ionising effect alpha high … … beta fast‑moving electron medium medium gamma electromagnetic radiation low … (i) Complete Table 12.1. [2] (ii) Fig. 12.1 shows the path taken by a beta particle as it moves through an electric field. Complete Fig. 12.1 to show the paths taken by alpha particles and gamma rays as they pass through an electric field. + − + − + − + − + − alpha beta gamma Fig. 12.1 [2] (b) Beta particles are released when carbon‑14 (146C) decays into an isotope of nitrogen. Use the correct nuclide notation to complete the decay equation for carbon‑14. 14 … … 6C … N + … β [2] (c) At room temperature, nitrogen is a gas, water is a liquid and carbon is a solid. (i) Explain why a gas can be compressed and a solid cannot be compressed. … … … [1] (ii) Suggest if water can be compressed. Give a reason for your answer. … … … [1] (iii) A sample of nitrogen gas is held in a container with a fixed volume. The temperature of the nitrogen is increased. Explain the effect that increasing the temperature of the gas has on the pressure in the gas. Use ideas about molecules in your answer. … … … … … … [3] [Total: 11]

11 marks

Mark scheme: 12(a)(i) He nucleus / 2 protons and 2 neutrons and low ; high ; 2 12(a)(ii) alpha curves towards negative ; gamma does not deviate ; 2 12(b)     14 14 0 6 7 1 C N ;; 2 12(c)(i) in a gas the particles are far apart / in a solid the particles are touching ; or in a gas the particles can be pushed closer together / the particles in a solid can’t be pushed closer together ; 1 12(c)(ii) (water cannot be compressed) (because) the molecules are touching or there are no / small, gaps between molecules ; 1 Question Answer Marks 12(c)(iii) (kinetic) energy / speed of molecules, increases ; molecules collide with the (walls of the) container, more often / harder ; the force per unit area increases / the pressure increases ; 3

This question in 0654/42 May/June 2023

12 X‑rays are part of the electromagnetic spectrum. Hospitals use X‑rays for medical imaging. (a) (i) State the speed of X‑rays. … m / s [1] (ii) An X‑ray machine in a hospital uses X‑rays with a wavelength of 2.0 × 10–11 m. Calculate the frequency of these X‑rays. frequency = … Hz [2] (b) Hospitals also use ultrasound waves for medical imaging. (i) Ultrasound waves are high frequency sound waves which are longitudinal. X‑rays are transverse waves. Complete the sentences to describe the nature of longitudinal and transverse waves. Longitudinal waves are produced by vibrations that are … to the direction of energy transfer. Transverse waves are produced by vibrations that are … to the direction of energy transfer. [1] (ii) During an ultrasound scan, ultrasound waves travel through gaseous air, solid bone and liquid blood. Sound waves, including ultrasound waves, travel at different speeds in gases, solids and liquids. Place the speed of sound in a gas, a solid and a liquid in order from fastest to slowest. fastest … … slowest … [1] (c) Hospitals use radioactive tracers such as technetium‑99 (9943 Tc) for medical imaging. (i) 9943 Tc has a half‑life of 6 hours. Calculate the percentage of 9943 Tc remaining in a sample after 24 hours. percentage remaining = … % [2] (ii) 9943 Tc is produced in hospitals from molybdenum‑99 (9942Mo). Use the correct nuclide notation to complete the decay equation for molybdenum‑99. 99 99 … … [1] 42Mo 43 Tc + … [Total: 8]

8 marks

Mark scheme: 12(a)(i) 12(a)(ii) (f =) v /  / 3  108 / 2.0  10–11 ; (f =) 1.5  1019 (Hz) ; 2 12(b)(i) parallel AND perpendicular ; 1 12(b)(ii) solid liquid gas ; 1 12(c)(i) 4 half-lives ; 6.25 (%) ; 2 12(c)(ii) 0 1  ; 1

This question in 0654/43 May/June 2023

3 Nuclear power stations use nuclear fission to generate electricity. The nuclear fission of uranium releases thermal energy. The thermal energy produced is used to convert water into steam which drives the turbines that generate electricity. (a) State one advantage of generating electricity from nuclear fission. … … [1] (b) Barium-141 (14156Ba) is produced by the nuclear fission of uranium. Barium-141 decays by emitting a beta-particle. (i) Use the correct nuclide notation to show the decay of barium-141. 141 … … 56Ba … La + … β [2] (ii) A 160 g sample of barium-141 has a half-life of 18 minutes. Calculate the time it will take for the mass of barium-141 in the sample to decrease to 10 g. time = … minutes [2] (c) Fig. 3.1 shows a simple turbine, similar to those used in a nuclear power station. blade A high-pressure steam d direction of rotation Fig. 3.1 (i) The high-pressure steam is at a pressure of 1.8 × 107 Pa. Blade A has a surface area of 0.12 m2. Show that the force acting on blade A is 2.2 × 106 N. [1] (ii) The moment of the force, from the high-pressure steam acting on blade A, is 1.35 × 106 N m. Calculate the distance d, from the centre of blade A to the pivot of the turbine. distance d = … m [2] (iii) When the turbine spins, blade A moves with a constant speed but a changing velocity. Explain why the velocity of blade A changes. … … [1] [Total: 9]

9 marks

Mark scheme: 3(a) any one from: 1 does not release, greenhouse gases / CO2 ; does not contribute to, global warming / climate change ; 3(b)(i) 141 56Ba → 14157La + -10β 2 La correct ; β correct ; 3(b)(ii) use of 4 half lives ; 2 (4  18 =) 72 (minutes) ; 3(c)(i) 1.8  107  0.12 ; 1 3(c)(ii) (d =) m ÷ f / (d =) 1.35  106 ÷ 2.2  106 ; 2 (d =) 0.61 or 0.63 (m) ; 3(c)(iii) the direction (of blade A) changes ; 1

This question in 0654/41 Oct/Nov 2023

12 Radon is a radioactive gas which occurs naturally in rocks and soil. (a) Radon-222 (22286Ra) is an unstable isotope which decays by emitting an alpha particle. (i) Use the correct nuclide notation to show the decay of radon-222. 222 … … 86Ra … Po + … α [2] (ii) Draw lines to match an alpha particle with its correct characteristics. One line has been drawn as an example. has a charge of 0 has a charge of –1 has a charge of +2 has a mass of 0 has a mass of 2 alpha particle has a mass of 4 has a low ionizing ability has a high ionizing ability can penetrate paper can penetrate aluminium can penetrate lead [1] (iii) Complete Fig. 12.1 to show the path of an alpha particle as it travels through the electric field between two charged plates. [1] + – + – + – + – + – alpha Fig. 12.1 (b) A sample of radon gas is stored in a container with a fixed volume. (i) Explain, in terms of the molecular motion, why the pressure in the radon gas increases when the temperature is increased. … … … … … [3] (ii) The volume of the container is 0.050 m3. The density of the radon gas is 9.7 kg / m3. Calculate the weight of the radon gas in the container. The gravitational field strength, g, is 10 N / kg. weight = … N [3] [Total: 10]

10 marks

Mark scheme: 12(a)(i) 222 86Ra → 21884 Po + 42 2 Po correct ;  correct ; 12(a)(ii) 1 has a mass of 4 and has a high ionising ability ; 12(a)(iii) 1 line curved to the right ; 12(b)(i) kinetic energy/speed of atoms increases ; 3 atoms collide with walls of container more often ; which exerts a larger force per unit area ; 12(b)(ii) (m =) V ; 3 (m = 9.7  0.05) 0.485 (kg) ; (W = mg = 0.485  10 =) 4.9 (N) ;

This question in 0654/42 Oct/Nov 2023

9 Tellurium is a rare element which exists as several isotopes, some of which are unstable. (a) A nucleus of tellurium-109 decays by emitting an alpha-particle. (i) Describe the effect of emitting an alpha-particle on the proton number (Z), number of neutrons and nucleon number (A) of a nucleus. proton number (Z) … number of neutrons: … nucleon number (A) … [2] (ii) The decay of tellurium-109 produces an isotope of tin. The half-life of tellurium-109 is 4.63 s. Calculate the time taken for a sample of pure tellurium-109 to contain 87.5% tin. time = … s [3] (b) Stable isotopes of tellurium can be used to make solar cells. (i) State one advantage and one disadvantage of using solar cells to generate electricity. advantage … … disadvantage … … [2] (ii) Suggest why it is an advantage for a solar cell to be coloured black. … … [1] (iii) Fig. 9.1 shows a panel of solar cells. 0.5 m 1.5 m Fig. 9.1 On a sunny day, there is 1400 W / m2 of sunlight hitting the solar cells shown in Fig. 9.1. The solar cells have an efficiency of 16%. Calculate the power output from the solar cells. power output = … W [3] [Total: 11]

11 marks

Mark scheme: 9(a)(i) reduces by 2 2 reduces by 2 reduces by 4 ;; one or two correct - 1 mark three correct - 2 marks 9(a)(ii) 12.5% of Te remaining ; 3 3 half-lives ; (4.63  3 = ) 13.89 or 13.9 (s) ; 9(b)(i) (advantage) doesn’t produce CO2 / contribute to global warming / climate change / AVP ; 2 (disadvantage) doesn’t work at night / need large area / AVP ; 9(b)(ii) black absorbs the most / is a good absorber of light / radiation ; 1 9(b)(iii) (power input = ) 1.5  0.5  1400 / 0.75  1400 / 1050 (W) ; 3 (power output =) power input  efficiency / 100 / 1050  0.16 ; (power output =) 168 (W) ; or 1400  0.16 = 224 ; 224  0.75 ; 168 (W) ;

This question in 0654/43 Oct/Nov 2023

6 Asteroids are large rocks which orbit the Sun. Fig. 6.1 shows a diagram of an asteroid. Fig. 6.1 (a) Fig. 6.2 shows the asteroid orbiting the Sun. 3.8×1011m Sun Not to scale Fig. 6.2 It takes 1245 days for the asteroid to complete one full orbit of the Sun. The asteroid orbits in a circle 3.8 × 1011 m from the Sun. Show that the average speed of the asteroid is 22 000 m / s. [3] (b) Scientists have found evidence that asteroids contain the isotope strontium-87. (i) Strontium-87 is produced by the decay of rubidium-87. Use correct nuclide notation to complete the decay equation for rubidium-87. 87 Rb 87 Sr + … … 37 38 … [1] (ii) Fig. 6.3 shows how a sample of rubidium-87 decays. 100 90 80 70 60 rubidium-87 remaining 50 in sample / % 40 30 20 10 0 0 50 100 150 200 time / billion years Fig. 6.3 Use Fig. 6.3 to determine the half-life of rubidium-87. Give a suitable unit for your answer. half-life = … unit … [2] (iii) Asteroids are thought to be 5 billion years old. Use Fig. 6.3 to determine the percentage of rubidium-87 that has decayed to strontium-87 in the asteroid. percentage = … % [1] [Total: 7]

7 marks

Mark scheme: 6(a) (1245 days =) 1.1  108 (s) ; 3 (d=) 2r OR 2  3.8  1011 OR 2.4  1012 (m) ; (distance / time) OR 2.4  1012 / 1.1  108 (= 22 196 OR 22 000 m / s); 6(b)(i) −;01 1 6(b)(ii) 50 ; 2 billion years ; 6(b)(iii) 7 (%) ; 1

This question in 0654/42 Feb/March 2024

9 The element strontium has many naturally occurring isotopes, some of which are unstable. (a) Table 9.1 shows the half‑lives of four unstable isotopes of strontium. Table 9.1 isotope half‑life strontium‑82 25.4 days strontium‑83 1.35 days strontium‑85 64.8 days strontium‑90 28.9 years (i) Fig. 9.1 shows a decay curve for one of the isotopes given in Table 9.1. 800 700 600 500 activity 400 / counts per minute 300 200 100 0 0 20 40 60 80 time / days Fig. 9.1 Determine which isotope of strontium from Table 9.1 would give the data shown in Fig. 9.1. isotope … [2] (ii) A scientist purchases a sample of a strontium isotope to use as a radioactive source in a series of experiments. The scientist estimates that the experiments will take three months to complete. Suggest which of the isotopes in Table 9.1 would be best for the scientist to purchase. Explain your suggestion. isotope … explanation … … … [1] (b) Place ticks (✓) in Table 9.2 to show the nature of a beta particle. Table 9.2 has a positive charge has a negative charge has no charge is affected by electric fields is affected by magnetic fields is not affected by electric or magnetic fields [2] (c) The density of strontium is 2.6 g / cm3. A sample of strontium has a mass of 7.8 g. Calculate the volume of the sample of strontium. volume = … cm3 [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) half-life calculated from graph ; strontium-82 ; 2 9(a)(ii) strontium-90 AND it will not need to be replaced for a long time / will last for a long time / will not run out quickly / owtte ; 1 9(b) has a negative charge ; is affected by electric fields AND is affected by magnetic fields ; 2 9(c) (V=) m /  OR 7.8 / 2.6 ; (V=) 3.0 (cm3) ; 2

This question in 0654/42 May/June 2024

12 (a) Fig. 12.1 shows the path taken by an alpha particle as it passes through an electric field. + – + – + – + – + – alpha beta gamma Fig. 12.1 (i) On Fig. 12.1, draw the paths taken by a beta particle and a gamma ray as they pass through the electric field. [2] (ii) Draw four lines to give the nature, relative ionising ability and relative penetrating ability of an alpha particle. has no mass has a relative mass of 4 has a relative mass of 1 has no charge has a relative charge of +2 an alpha particle has a relative charge of –1 has a high ionising ability has a low ionising ability has a high penetrating ability has a low penetrating ability [3] (b) Nuclear power stations use nuclear fission to generate electricity. (i) A nuclear power station generates 6.7 × 106 J of energy per day. The efficiency of the power station is 89%. Calculate the useful energy output from the power station in one year. useful energy output in one year = … J [3] (ii) State one advantage of generating electricity using nuclear fission compared to using fossil fuels. … … [1] (iii) The nuclear power station uses a generator to produce electrical energy. Fig. 12.2 shows a diagram of a simple a.c. generator. permanent magnets S slip rings coil N output potential difference Fig. 12.2 Describe how a simple a.c. generator produces an output potential difference. Include a description of the role of the slip rings in your answer. … … … … … … [4] [Total: 13]

13 marks

Mark scheme: 12(a)(i) beta curves to left ; gamma moves straight through ; 2 12(a)(ii) has a relative mass of 4 ; has a relative charge of +2 ; has a high ionising ability and has a low penetrating ability ; 3 12(b)(i) (useful energy output =) 89  6.7  106 /100 / 5.96  106 J per day ; (useful energy output =) 5.96  106  365 ; (useful energy output =) 2.2  109 (J) ; 3 12(b)(ii) does not release carbon dioxide / contribute to global warming / climate change ; 1 12(b)(iii) coil rotates ; coil cuts magnetic field / experiences a changing magnetic field ; emf / current is induced in the coil ; slip rings maintain electrical contact / prevent wires from tangling / ; 4

This question in 0654/43 May/June 2024

9 Tritium (31H) is an isotope of hydrogen. (a) Tritium decays by beta (β) emission. (i) Use correct nuclide notation to complete the decay equation for tritium. 1H3 … He + … β [3] (ii) The half‑life of tritium is 12.3 years. Calculate the time taken, in years, for 87.5% of a sample of tritium to decay. time = … years [2] (b) A beta particle is emitted from a tritium nucleus with a speed of 2.0 × 108 m / s and a kinetic energy of 1.8 × 10–14 J. (i) Calculate the distance travelled by the beta particle in 3.5 × 10–10 s. distance = … m [2] (ii) Calculate the mass of the beta particle. mass = … kg [2] [Total: 9]

9 marks

Mark scheme: 9(a)(i) 3 1H → 32 He+ -10 β 3 1 mark for correct nucleon number for He ; 1 mark for correct proton number for He ; 1 mark for correct beta particle ; 9(a)(ii) reference to 3 half-lives or 12.3  3 ; 2 36.9 (years) ; 9(b)(i) (d =) v  t or 2.0  108  3.5  10–10 ; 2 (d =) 0.070 (m) ; 9(b)(ii) (2  1.8  10 −14 ) 2 evidence of KE = ½ mv2 or ; (2.0  108 )2 9.0  10–31 (kg)

This question in 0654/41 Oct/Nov 2024

12 Polonium is a highly radioactive metal with no stable isotopes. (a) Polonium-210 (21084Po) decays to form lead-206 (20682Pb). The decay of polonium-210 is a one-step process. (i) State the type of ionising radiation emitted when polonium-210 decays to lead-206. … [1] (ii) The half-life of polonium-210 is 140 days. The activity of a sample of polonium-210 is measured as 680 counts per minute. Calculate the time taken, in days, for the activity to decrease to 85 counts per minute. time = … days [2] (b) Polonium is a solid at room temperature. The melting point of polonium is 254 °C. (i) Explain, in terms of the motion and arrangement of atoms, why a fixed mass of solid polonium will occupy a smaller volume than the same mass of liquid polonium. … … … … … … [3] (ii) The density of solid polonium is 9.4 g / cm3. Calculate the volume occupied by 235 g of solid polonium. volume = … cm3 [2] [Total: 8]

8 marks

Mark scheme: 12(a)(i) alpha (particle) ; 1 12(a)(ii) reference to 3 half-lives ; 2 (140  3 =) 420 (days) ; 12(b)(i) idea that, both samples contain the same number of atoms (as they have the same mass) ; 3 atoms in a solid vibrate (about fixed positions) and atoms in a liquid are free to move ; atoms in a solid are in a regular arrangement and atoms in a liquid are in a random / irregular arrangement (so take up more space) ; 12(b)(ii) evidence of V = m ÷ or 235 ÷ 9.4 ; 2 (V =) 25 (cm3) ;

This question in 0654/42 Oct/Nov 2024

12 Fig. 12.1 shows a diagram of a nuclear power station used to generate electricity. boiler control rod steam fuel rod moderator steam turbine generator to cooling tower reactor pump condenser Fig. 12.1 (a) (i) State the process in the reactor that releases energy. … [1] (ii) Complete the sentence about energy resources. The Sun is the source of energy for all our energy resources except nuclear, … and tidal. [1] (b) (i) Describe, in terms of molecules, how the steam exerts pressure on the walls of the boiler. … … … … [2] (ii) The steam in the boiler has a constant volume. State what happens to the pressure of the steam if the temperature of the steam is increased. … [1] (c) The power station uses an alternating current (a.c.) generator to generate electricity. Fig. 12.2 shows a simple a.c. generator. direction of rotation S coil N output potential difference Fig. 12.2 (i) Describe how a simple a.c. generator produces an output potential difference (p.d.). … … … … … [2] (ii) The generator converts kinetic energy into electrical energy. The efficiency of the generator is 75%. Calculate the kinetic energy required to produce 3600 J of electrical energy. kinetic energy = … J [2] (d) The fuel rod contains uranium-235 (23592U). Uranium-235 decays by alpha emission. Use correct nuclide notation to complete the decay equation for uranium-235. 235 … … 92U … Th + … α [2] [Total: 11]

11 marks

Mark scheme: 12(a)(i) (nuclear) fission ; 1 12(a)(ii) geothermal ; 1 12(b)(i) molecules (of steam) collide with the walls / container ; 2 (collisions) exert a force (on the walls) ; 12(b)(ii) increases ; 1 12(c)(i) rotating coil experiences a changing magnetic, field / flux ; 2 (output p.d.) is induced / reference to electromagnetic induction ; 12(c)(ii) evidence of (KE / input energy) = output / efficiency  100 or 3600 / 75 100 ; 2 4800 (J) ; 12(d) 235 231 4 2 92 U → 90Th + 2  thorium correct ; alpha correct ;

This question in 0654/43 Oct/Nov 2024

11 (a) 38Sr is a radioactive isotope. It undergoes beta decay with a half-life of 29 years. (i) Complete the equation for this nuclear decay. 90 … … 38Sr … Y + … β [3] 90 (ii) The mass of 38Sr in a sample is 1.6 mg. 90 Calculate the mass of 38Sr isotope remaining after 58 years. mass … mg [1] 90 (iii) A 38Sr source is used in a factory making aluminium foils. Describe three ways in which workers are kept safe from the effects of the radiation. 1 … 2 … 3 … [3] (b) Space vehicles used to explore the Moon can be powered by radioactive sources. The Moon takes 27.3 days to orbit the Earth. The mean distance from the Earth to the Moon is 3.84 × 108 m. Calculate the mean orbital speed of the Moon around the Earth. speed = … m / s [2] [Total: 9]

9 marks

Mark scheme: 11(a)(i) beta with 0, –1; 3 (top row 90) 90Y ; (bottom row 39) 39Y ; 11(a)(ii) 0.4 (mg) ; 1 11(a)(iii) any three from: 3 minimise exposure time maximise distance use shielding radiation detection badge ; ; ; 11(b) evidence of v=2r / T or 2    3.84  108 or (27.3  24  3600) ; 2 1020 (m / s) ;

This question in 0654/42 Feb/March 2025

11 (a) The isotope carbon-14 (C-14) decays to form an isotope of nitrogen (N) by emitting a beta particle. Complete the decay equation for this nuclear decay. 14 … … 6C … β + … N [2] (b) Thin aluminium foil is manufactured by passing thick sheets of aluminium between rollers. Radioactive sources are used to measure and control the thickness of the aluminium foil, as shown in Fig. 11.1. radioactive rollers source aluminium radiation detector machinery to control rollers Fig. 11.1 Suggest which type of radiation would be suitable for use in measuring and controlling the thickness of the aluminium foil. Explain your answer. radiation … explanation … … … [3] (c) Carbon-14 has a half-life of 5700 years. A 5.0 g sample of wood from a living tree has an activity of 28 counts per minute due to the decay of carbon-14. A 5.0 g sample of dead wood from the hull of an ancient wooden boat has an activity of 7 counts per minute due to the decay of carbon-14. Calculate the age of the wood from the hull of the boat. age = … years [2] (d) Nuclear reactions occur in stable stars. (i) State the type of nuclear reactions that take place in a stable star. … [1] (ii) State what is produced in these nuclear reactions. … … [2] [Total: 10]

10 marks

Mark scheme: 11(a) 14 0 14 2 6 C → –1+ 7 N beta completely correct = 1 mark N completely correct = 1 mark 11(b) beta ; 3 and (for 1 mark) (beta) penetrates (through thin) aluminium foil (to be detected) / (beta) absorbed (by thick) aluminium foil (so not detected) ; but (for 2 marks) (beta) penetrates through thin aluminium foil (to be detected) / (beta) absorbed by thick aluminium foil (so not detected) ; 11(c) 2 half-lives ; 2 11 400 years ; 11(d)(i) fusion ; 1 11(d)(ii) helium ; 2 and one from: • any named product heavier than hydrogen but lighter than iron ; • energy ;

This question in 0654/41 Oct/Nov 2025

11 (a) (i) State the age of the Universe according to the Big Bang Theory. … [1] (ii) State how the Universe began according to the Big Bang Theory. … … [2] (b) The distance between Earth and Mars varies between 5.6 × 1010 m and 4.0 × 1011 m. Calculate the shortest possible time for light to travel from Earth to Mars. time = … s [2] (c) (i) New elements form during radioactive decay. 21 0 is radioactive. It decays by emitting an alpha particle. 8 4Po Complete the equation for this nuclear decay. 21 0 … … Pb + α 8 4Po … … [2] (ii) Initially a sample of 21 0 has a mass of 560 g. 8 4Po The half-life of 21 0 is 3.1 minutes. 8 4Po Calculate the mass of 21 0 remaining after 12.4 minutes. 8 4Po mass = … g [2] [Total: 9]

9 marks

Mark scheme: 11(a)(i) 13.8 billion years ; 1 11(a)(ii) expanded ; 2 from a single point (of high temperature / high density) ; 11(b) time = distance / speed or t = s / v (in this form) or 5.6  1010 / 3  108 ; 2 187 / 190 (s) ; 11(c)(i) 210 206 4 2 84 Po → 82 Pb + 2 alpha completely correct ; Pb completely correct ; 11(c)(ii) (12.4 / 3.1 =) 4 (half-lives) ; 2 (560 / 24 =) 35 (g) ;

This question in 0654/43 Oct/Nov 2025