Q1. In the early part of the 20th century scientists used the plum pudding model to explain the structure of the atom.... (1)

Transcription

1 Q. In the early part of the 20th century scientists used the plum pudding model to explain the structure of the atom. (a) What did scientists think that the pudding part of the atom was? () The scientists Geiger and Marsden devised an experiment to test the plum pudding model. They fired positively charged alpha particles at a very thin sheet of gold foil. They then measured the different paths taken by the alpha particles. List A gives some of the observations from the experiment. List B gives the conclusions reached from the observations. Draw one line from each observation in List A to the conclusion reached in List B. List A Observation List B Conclusion Page of 43

2 (c) Following the work of Geiger and Marsden, the plum pudding model of the atom was replaced by the nuclear model of the atom. Explain why it is sometimes necessary for scientists to replace a scientific model. (Total 5 marks) Q2. (a) The diagram shows a hammer which is just about to drive a nail into a block of wood. The mass of the hammer is 0.75 kg and its velocity, just before it hits the nail, is 5.0 m/s downward. After hitting the nail, the hammer remains in contact with it for 0. s. After this time both the hammer and the nail have stopped moving. (i) Write down the equation, in words, which you need to use to calculate momentum. () What is the momentum of the hammer just before it hits the nail? Show how you work out your answer and give the units and direction. Momentum =... (3) Page 2 of 43

3 (iii) What is the change in momentum of the hammer during the time it is in contact with the nail? () (iv) Write down an equation which connects change in momentum, force and time. () (v) Calculate the force applied by the hammer to the nail. Show how you work out your answer and give the unit. Force =... (3) A magazine article states that: Wearing a seat belt can save your life in a car crash. Use your understanding of momentum to explain how this is correct (4) (Total 3 marks) Page 3 of 43

4 Q3. (a) Nuclear power stations use the energy released by nuclear fission to generate electricity. (i) Explain what is meant by nuclear fission. How does nuclear fission lead to a chain reaction? You may give your answer as a labelled diagram. () Although nuclear fuels are relatively cheap the total cost of generating electricity using nuclear fuels is expensive. Why? () (c) The table compares the energy released from kg of coal and kg of uranium. Coal 29 MJ MJ = joules Uranium MJ State one benefit to the environment of using a concentrated fuel like uranium to generate electricity rather than using the energy from coal () (Total 5 marks) Page 4 of 43

5 Q4. A set of Christmas tree lights is made from twenty identical lamps connected in series. (a) Each lamp is designed to take a current of 0.25 A. The set plugs directly into the 230 V mains electricity supply. (i) Write down the equation that links current, potential difference and resistance..... () Calculate the resistance of one of the lamps. Show clearly how you work out your final answer and give the unit Resistance =... (4) (iii) What is the total resistance of the set of lights?.... Total resistance =... () Page 5 of 43

6 How does the resistance of a filament lamp change as the temperature of the filament changes? () (Total 7 marks) Q5. The statement in the box is from an article in a science magazine. Scientists think that all the elements on Earth are also present throughout the Universe. (a) (i) Name the process by which these elements were formed... () Where did the elements form?.. () (iii) What caused these elements to be distributed throughout the Universe?.. () Scientists have only examined a tiny fraction of the Universe. What is the basis for the statement in the science magazine? () (Total 4 marks) Page 6 of 43

7 Q6. The diagram shows two oscilloscope traces, A and B. Trace A shows how the potential difference between the live and neutral terminals of an electricity supply changes with time. (a) Describe how the potential of the live terminal varies with respect to the neutral terminal of the electricity supply What does trace B show? () (c) Each horizontal division on the oscilloscope represents s. (i) What is the period of this electricity supply?.. Period =... seconds () Calculate the frequency of the supply... Frequency =... hertz () (Total 5 marks) Page 7 of 43

8 Q7. (a) The diagram shows an aircraft and the horizontal forces acting on it as it moves along a runway. The resultant force on the aircraft is zero. (i) What is meant by the term resultant force? () Describe the movement of the aircraft when the resultant force is zero. () The aircraft has a take-off mass of kg. Each of the 4 engines can produce a maximum force of 240 kn. Use the equation in the box to calculate the maximum acceleration of the aircraft. resultant force = mass acceleration Show clearly how you work out your answer and give the unit Acceleration =... (3) Page 8 of 43

9 (c) As the aircraft moves along the runway to take off, its acceleration decreases even though the force from the engines is constant. Explain why (Total 7 marks) Q8. The diagram shows someone accidentally touching the live wire inside a dismantled 230 volt mains electricity socket. A current flows through the person giving him an electric shock. (a) (i) Use the equation in the box to calculate the current that will flow through the person. potential difference = current resistance Show clearly how you work out your answer. Current =... A Page 9 of 43

10 Rubber is a good insulator. Explain why it is a good idea for electricians to wear rubber soled boots when working. If the current flowing through a person is too high, the person cannot let go of the electrical source. Different people were tested to see whether the ability to let go of an electrical source depended on the frequency of the current. The results of the test are shown in the graph. (i) What is the frequency of the mains electricity supply in the UK?... () From a safety point of view, is the frequency of the UK mains electricity supply suitable? Give a reason for your answer. () Page 0 of 43

11 (c) The diagram shows how the electric supply cable is connected to an electric kettle. The earth wire is connected to the metal case of the kettle. If a fault makes the metal case live, the earth wire and the fuse inside the plug protect anyone using the kettle from an electric shock. Explain how (Total 8 marks) Q9. (a) The diagram shows the parts of a smoke detector. The radioactive source emits alpha particles. The alpha particles ionise the air inside the sensor which causes a small electric current. Any smoke getting into the sensor changes the current. The change in current sets the alarm off. Page of 43

12 (i) The smoke detector would not work if a radioactive source that emitted only gamma rays was used. Why not? () Curium-242 is a radioactive isotope with a half-life of 60 days. It emits alpha particles. Why is curium-242 not suitable for use inside smoke detectors? () (iii) Curium-242 and curium-244 are two of the isotopes of the element curium. How is an atom of curium-242 different from an atom of curium-244? () Sections of steel are often joined by welding them together. The diagram shows how a radioactive source can be used to check for tiny cracks in the weld. Cracks in the weld will be shown up on the photographic film below the thick steel plate. (i) Which type of source, alpha, beta or gamma, should be used to check the weld?... () Give a reason why the other two types of source cannot be used. () Page 2 of 43

13 (c) The diagram shows a map of a river and its estuary. Environmental scientists have found that the water flowing into one part of the river estuary is polluted. To find where the pollution is coming from, the scientists use a radioactive isotope, gold-98. (i) Explain how the gold-98 is used to find where the pollution is coming from. Page 3 of 43

14 The graph shows how the count rate from a sample of gold-98 changes with time. Use the graph to calculate the half-life of gold-98. Show clearly on the graph how you obtain your answer. Half-life =... days (Total 9 marks) Page 4 of 43

15 Q0. (a) The diagram shows what can happen when the nucleus of a uranium atom absorbs a neutron. (i) What name is given to the process shown in the diagram? () Explain how this process could lead to a chain reaction. You may wish to add further detail to the diagram to help your answer. (iii) How does the mass number of an atom change when its nucleus absorbs a neutron? () Page 5 of 43

16 Uranium-235 is used as a fuel in some nuclear reactors. Source: adapted from Physics Matters, by Nick England. Published by Hodder and Stoughton, 989. Reproduced by permission of Hodder and Stoughton Ltd. The reactor contains control rods used to absorb neutrons. Suggest what happens when the control rods are lowered into the reactor (Total 6 marks) Q. The diagram shows a motorbike of mass 300 kg being ridden along a straight road. The rider sees a traffic queue ahead. He applies the brakes and reduces the speed of the motorbike from 8 m/s to 3 m/s. Page 6 of 43

17 (a) Use the equation in the box to calculate the kinetic energy lost by the motorbike. kinetic energy = mass speed 2 Show clearly how you work out your answer Kinetic energy lost =... J (i) How much work is done on the motorbike by the braking force? () What happens to the kinetic energy lost by the motorbike? () (Total 4 marks) Q2. The diagram shows a child on a playground swing. The playground has a rubber safety surface. Page 7 of 43

18 (a) The child, with a mass of 35 kg, falls off the swing and hits the ground at a speed of 6 m/s. (i) Use the equation in the box to calculate the momentum of the child as it hits the ground. momentum = mass velocity Show clearly how you work out your answer and give the unit. Momentum =... (3) After hitting the ground, the child slows down and stops in 0.25 s. Use the equation in the box to calculate the force exerted by the ground on the child. force = Show clearly how you work out your answer. Force =... N The diagram shows the type of rubber tile used to cover the playground surface. Explain how the rubber tiles reduce the risk of children being seriously injured when they fall off the playground equipment (3) Page 8 of 43

19 (c) The critical fall height is the height that a child can fall and not be expected to sustain a life-threatening head injury. A new type of tile, made in a range of different thicknesses, was tested in a laboratory using test dummies and the critical fall height measured. Only one test was completed on each tile. The results are shown in the graph. The critical fall height for playground equipment varies from 0.5 m to 3.0 m. Suggest two reasons why more tests are needed before this new type of tile can be used in a playground (d) Developments in technology allow manufacturers to make rubber tiles from scrap car tyres. Suggest why this process may benefit the environment () (Total marks) Page 9 of 43

20 Q3. Read this statement from a website. Immediately after the big bang, at the start of the Universe, there were only atoms of the element hydrogen (H). Now the Universe contains atoms of over one hundred elements. (a) Explain how atoms of the element helium (He) are formed in a star Explain how atoms of very heavy elements, such as gold (Au), were formed (c) Explain how, and when, atoms of different elements may be distributed throughout the Universe (Total 6 marks) Q4. Most elements have some isotopes which are radioactive. (a) What is meant by the terms: (i) isotopes () Page 20 of 43

21 radioactive? () The graph shows how the number of nuclei in a sample of the radioactive isotope plutonium-238 changes with time. Use the graph to find the half-life of plutonium-238. Show clearly on the graph how you obtain your answer. Half-life =... years (c) The Cassini spacecraft launched in 997 took seven years to reach Saturn. The electricity to power the instruments on board the spacecraft is generated using the heat produced from the decay of plutonium-238. (i) Plutonium-238 decays by emitting alpha particles. What is an alpha particle? () Page 2 of 43

22 During the years that Cassini will orbit Saturn, the output from the generators will decrease. Explain why. (d) Plutonium-238 is highly dangerous. A tiny amount taken into the body is enough to kill a human. (i) Plutonium-238 is unlikely to cause any harm if it is outside the body but is likely to kill if it is inside the body. Explain why. In 964, a satellite powered by plutonium-238 was destroyed, causing the release of radioactive material into the atmosphere. Suggest why some environmental groups protested about the launch of Cassini. () (Total 0 marks) Q5. (a) Describe the difference between an alternating current (a.c.) and a direct current (d.c.) Page 22 of 43

23 The diagram shows the information plate on the bottom of an electric wallpaper steamer. (i) Use the equation in the box to calculate the current used by the steamer. power = current potential difference Show clearly how you work out your answer. Current... A Which one of the following fuses should be used inside the plug of the steamer? Draw a ring around your answer. A 3 A 5 A 0 A 3 A () (Total 5 marks) Q6. The diagram shows the horizontal forces acting on a car of mass 200 kg. Page 23 of 43

24 (a) Calculate the acceleration of the car at the instant shown in the diagram. Write down the equation you use, and then show clearly how you work out your answer and give the unit. Acceleration =... (4) Explain why the car reaches a top speed even though the thrust force remains constant at 3500 N. (3) Page 24 of 43

25 (c) The diagram shows a car and a van. The two vehicles have the same mass and identical engines. Explain why the top speed of the car is higher than the top speed of the van. (4) (Total marks) Q7. In the UK mains electricity is a 230 volt a.c. supply. (a) What is the frequency of the a.c. mains electricity in the UK? () (i) What is an electric current?... () Explain the difference between an a.c. (alternating current) electricity supply and a d.c. (direct current) electricity supply Page 25 of 43

26 (c) A householder has a 0.8 kw electric shower installed in the bathroom. (i) Calculate the current drawn from the mains electricity supply by the shower. Write down the equation you use, and then show clearly how you work out your answer Current =... A The table gives the maximum current that can safely pass through electric cables of different cross-sectional area. Cross-sectional area in mm 2 Maximum safe current in amps The existing power sockets in the house are wired to the mains electricity supply using 2.5 mm 2 cable. Use the data in the table to explain why the shower must not be connected to the mains electricity supply using 2.5 mm 2 cable Page 26 of 43

27 (iii) The circuit connecting the shower to the mains electricity supply must include a residual current circuit breaker (RCCB) and not a fuse. Give two advantages of using a RCCB to protect a circuit rather than a fuse (Total 0 marks) Q8. A car is driven along a straight, snow covered, road. The graph shows how the velocity of the car changes from the moment the driver sees a very slow moving queue of traffic ahead. (a) Use the graph to calculate the distance the car travels while it is slowing down. Show clearly how you work out your answer. Distance =... m (3) Page 27 of 43

28 The car has a mass of 200 kg. Calculate the kinetic of the car when it travels at a speed of 2 m/s. Write down the equation you use, and then show clearly how you work out your answer. Kinetic energy =... J (Total 5 marks) Page 28 of 43

29 M. (a) (mass of) positive charge three lines correct allow mark for correct line if more than line is drawn from a box in List A then all those lines are incorrect 2 (c) new scientific evidence / data is obtained which cannot be explained by the model [5] M2. (a) (i) momentum = mass velocity accept speed or any transposed version.2 to for mark kg m/s down(wards) or Ns down(ward) n.b. both unit and direction required for this mark (iii).2 to.3 accept same numerical answer as part (a) accept answer without any unit or with the same unit as in part (a), even if incorrect, but any other unit cancels the mark 2 Page 29 of 43

30 (iv) force = accept transposed version (v) 2 to 3 or numerical value from (a) or (a) 0. for mark newton(s) or N accept Newton(s) do not credit Ns or n 2 (the user will experience a) large change in momentum do not credit just momentum changes (but) seat belt increases the time for this to occur or seat belt stops you hitting something which would stop you quickly do not credit just stops you hitting the windscreen etc. (so) the force on the user is less(*) (so) less chance of (serious / fatal) injury(*) (*) depends on previous response re momentum or continued movement [3] Page 30 of 43

31 M3. (a) (i) (large) nucleus hit by a neutron splits into (smaller) nuclei and neutron(s) (+ energy) additional neutrons collide with nuclei causing further fission allow full credit for a correct labelled diagram accept 2 or more neutrons given out at each fission reaction diagram shows 3 discernible sizes, with smaller nuclei and neutrons at same stage cost of (building and) de-commissioning is very high or cost of building is higher accept a correct description of de-commissioning accept high cost to keep the power station safe / secure accept high cost of reprocessing / storage of nuclear waste (c) less pollution from transport carrying the fuel accept coal produces more pollutant gases accept correct named gases accept more radiation pollution from coal than nuclear accept more waste from coal than nuclear do not accept any reference to burning uranium do not accept answers in terms of global warming or acid rain unless developed [5] Page 3 of 43

32 M4. (a) (i) potential difference = current resistance accept voltage or pd for potential difference accept V = I R accept correct transformation do not accept V = C R do not accept V = A R accept provided subsequent use of Δ correct do not accept an equation expressed in units 46 credit correct transformation for mark allow mark for use of.5 V or division of final resistance by 20 a final answer of 920 gains 2 marks only 3 ohm(s) accept symbol Ω do not accept Ω s unit / symbol mark can be awarded in (iii) provided unit / symbol is omitted in (iii) 920 (ohms) or their (a) 20 as temperature increases, resistance increases accept hotter for temperature increase do not accept a reference to resistance only i.e. it / resistance goes up [7] M5. (a) (i) (nuclear) fusion allow minor misspellings but do not credit any response which could be fission (in) stars accept supernova / red giants / white dwarves do not allow the Sun Page 32 of 43

33 (iii) (by) supernova / explosion of star do not credit just explosion(s) the (available) evidence: supports this idea or does not contradict this idea or can be extrapolated to this idea [4] M6. (a) alternates accept switches accept (constantly) changes accept goes up and down between positive and negative potential difference between the neutral and earth (terminal) accept voltage for p.d or potential of the neutral terminal with respect to earth (c) (i) (s) 40 (Hz) accept their (a)(i) [5] M7. (a) (i) a single force that has the same effect as all the forces combined accept all the forces added / the sum of the forces / overall force constant speed (in a straight line) do not accept stationary or constant velocity Page 33 of 43

34 3 allow mark for correct substitution into transformed equation accept answer gains mark answer = 0.75 gains mark 2 m/s 2 (c) as speed increases air resistance increases accept drag / friction for air resistance reducing the resultant force [7] M8. (a) (i) accept 4.6 ma allow mark for correct substitution and transformation i.e. current = an answer of 4.6 gains mark 2 increases overall resistance (in event of a shock) gives a smaller current accept gives smaller shock do not accept no shock/current (i) 50 (hertz) ignore units NO has the lowest current at which people cannot let go answer and reason needed accept a sensible reason in terms of their answer to (i) or YES changing the frequency changes the current by only a small amount Page 34 of 43

35 (c) a current flows through from the live wire/metal case to the earth wire accept a current flows from live to earth do not accept on its own if the current is too high this current causes the fuse to melt accept blow for melt 2 [8] M9. (a) (i) gamma hardly ionises the air accept does not ionise accept gamma radiation is not charged do not accept answers in terms of danger of gamma or other properties half-life (too) short accept need frequent replacement it refers to curium-242 (iii) (two) fewer neutrons accept different numbers of neutrons if a number is specified it must be correct do not accept more neutrons unless curium-244 is specified (i) gamma accept correct symbol both absorbed by the metal / steel / weld only scores if (i) is correct accept cannot pass through the metal / steel / weld (c) (i) put source into water at one point on bank accept the idea of testing different parts of the river bank at different times see if radiation is detected in polluted area accept idea of tracing 2.7 (days) allow mark for showing correct use of the graph 2 [9] Page 35 of 43

36 M0. (a) (i) (nuclear) fission accept fision providing clearly not fusion (released) neutrons are absorbed by further (uranium) nuclei accept hit nuclei for absorbed / hit do not accept atom for nuclei more neutrons are released (when new nuclei split) accept for both marks a correctly drawn diagram (iii) increases by or goes up to 236 any two from: (more) neutrons are absorbed accept there are fewer neutrons (chain) reaction slows down / stops accept keeping the (chain) reaction controlled less energy released accept heat for energy accept gases (from reactor) are not as hot 2 [6] M. (a) answers of 350/ 33750/ gain mark allow mark for correct substitution using both 8 and 3 2 (i) or their (a) accept statement same as the KE (lost) ignore any units transformed into heat/ thermal energy sound on its own is insufficient accept transferred/ lost/ for transformed do not accept any other form of energy included as a list [4] Page 36 of 43

37 M2. (a) (i) 20 allow mark for correct substitution i.e kg m/s or Ns do not accept n for N accept g m/s for 3 marks if answer given is not 840 accept their (a)(i) in kg m/s 0.25 correctly calculated for both marks allow mark for correct substitution i.e or their (a)(i) increases the time to stop accept increases impact time do not accept any references to slowing down time decreases rate of change in momentum accept reduces acceleration/deceleration reduces momentum is insufficient reduces the force (on the child) (c) any two from: insufficient range of tests/thicknesses for required cfh accept need data for thicknesses above 80 mm/ cfh 2.7 m not enough tests is insufficient (seems to be) some anomalous data (repeats) needed to improve reliability (of data) accept data/ results are unreliable do not accept maybe systematic/random error do not accept reference to precision need to test greater range/variety of dummies accept children for dummies accept specific factor such as weight/height/size 2 (d) Tyres do not need to be dumped/burned/ less land-fill/ saves on raw materials accept less waste do not accept recycling on its own [] Page 37 of 43

38 M3. (a) fusion () of hydrogen/h (atoms)() do not credit any response which looks like fission or the word fussion credit only if a nuclear reaction 2 fusion of other/lighter atoms/elements () reference to big bang nullifies both marks during super nova/explosion of star(s) () 2 (c) explosion of star(s)/super nova () reference to big bang nullifies both marks reference to the star running out of energy/material nullifies both marks at the end of the life of star(s) / when they die () 2 [6] M4. (a) (i) (atoms / elements with) the same number of protons but different numbers of neutrons accept (atoms / elements with) different mass number but same atomic number substances that give out radiation accept alpha, beta or gamma for radiation accept an unstable nucleus that decays radioactive decay takes place is insufficient 85 years ± 2 years allow mark for showing correct method on the graph 2 (c) (i) a helium nucleus accept 2 neutrons and 2 protons accept 2 4 He do not accept helium atom Page 38 of 43

39 the rate of decay (of plutonium) decreases accept fewer (plutonium) nuclei (to decay) accept radioactivity decreases less heat produced do not accept energy for heat (d) (i) (outside the body) alpha (particles) cannot penetrate into the body (inside the body) (heat produced from decay) damages / kills cells / tissues accept causes cancer for damages / kills cells / tissues accept highly toxic any one from: worried same could happen again an accident may cause radiation to be spread around the Earth / atmosphere idea of soil contamination resulting from accident / release of radioactive material idea of negative effect on health resulting from accident / release of radioactive material accept any sensible suggestion [0] Page 39 of 43

40 M5. (a) d.c. flows in (only) one direction a.c. changes direction (twice every cycle) accept a.c. constantly changing direction ignore references to frequency accept answers presented as a clear diagram e.g. ac: (i) 0 allow mark for correct transformation and substitution i.e. an answer 0.0 gains mark 2 3 A e.c.f. accept the fuse size that is the next listed value greater than answer (i) [5] Page 40 of 43

41 M6. (a).25 allow mark for correct resultant force ie 500N allow 2 marks for correct transformation and substitution ie allow mark for a correct transformation but clearly substituting an incorrect value for force eg = 3 m/s 2 (c) as speed increases so does the size of the drag force accept frictional force / resistive force / air resistance for drag eventually the drag force becomes equal to the thrust the resultant force is now equal to zero and therefore there is no further acceleration the car and van will reach top speed when the forward force equals the drag force accept air resistance / frictional / resistive force for drag force the drag force at any speed is smaller for the car than for the van as the car is more streamlined therefore the car s drag force will equal the forward force at a higher speed allow converse throughout [] M7. (a) 50 hertz (i) a flow of charge / electrons a.c. is constantly changing direction whilst d.c. always flows in the same direction Page 4 of 43

42 (c) (i) 46.9 accept 47.0 allow mark for correct transformation and substitution ie 2 current (46.9 A) exceeds maximum safe current for 2.5 mm 2 cable accept cable needs to be 6.0 mm 2 therefore if a 2.5 mm 2 cable were used it would overheat / melt cable needs to be 0.0 mm 2 limits maximum credit to mark (iii) can be reset disconnects circuit faster (than a fuse) [0] M8. (a) 35 (m) allow mark for indicating the correct area allow mark for obtaining correct figures from the graph allow mark for calculating area of triangle (25) but omitting the rectangle underneath (2 x 5) allow mark for correct substitution into the correct equation ie / [5] Page 42 of 43

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