Q1. The graphs in List A show how the velocities of three vehicles change with time. The statements in List B describe different motions.

Transcription

1 Q. The graphs in List A show how the velocities of three vehicles change with time. The statements in List B describe different motions. Draw one line from each graph in List A to the description of the motion represented by that graph in List B. List A Velocity time graphs List B Descriptions of motion (Total 3 marks) Q2. The diagram shows the horizontal forces acting on a car of mass 200 kg. Page of 54

2 (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) (b) Explain why the car reaches a top speed even though the thrust force remains constant at 3500 N. (3) Page 2 of 54

3 (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) Q3. 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? () Page 3 of 54

4 (b) The scientists Geiger and Marsden devised an experiment to test the plum pudding model. They fired positively charged alpha particles at a very thin sheet of gold foil. They then measured the different paths taken by the alpha particles. List A gives some of the observations from the experiment. List B gives the conclusions reached from the observations. Draw one line from each observation in List A to the conclusion reached in List B. List A Observation List B Conclusion (c) Following the work of Geiger and Marsden, the plum pudding model of the atom was replaced by the nuclear model of the atom. Explain why it is sometimes necessary for scientists to replace a scientific model. (Total 5 marks) Page 4 of 54

5 Q4. The table gives information about the three types of particle that make up an atom. Particle Relative mass Relative charge Proton + Neutron Electron very small (a) (b) (c) Complete the table by adding the two missing values. Use the information in the table to explain why an atom has no overall electrical charge Uranium has two natural isotopes, uranium-235 and uranium-238. Uranium-235 is used as a fuel inside a nuclear reactor. Inside the reactor, atoms of uranium-235 are split and energy is released. (i) How is the structure of an atom of uranium-235 different from the structure of an atom of uranium-238? () The nucleus of a uranium-235 atom must absorb a particle before the atom is able to split. What type of particle is absorbed?... () (iii) The nucleus of an atom splits into smaller parts in a reactor. What name is given to this process?... () (Total 7 marks) Page 5 of 54

6 Q5. (a) The diagram shows a three-pin plug and electrical cable. Name a suitable material to make: the plug casing... the inner cores of the cable.... Give the reason for your choice of each material. plug casing... inner core of the cable... (4) Page 6 of 54

7 (b) The pictures show mains electricity being used to operate various devices. Some of the pictures show the electricity being used in a dangerous way. In the box underneath each picture put: a tick ( ) if the electricity is being used safely a cross ( ) if the electricity is being used dangerously. (Total 6 marks) Page 7 of 54

8 ## The table shows the braking distances for a car at different speeds and kinetic energy. The braking distance is how far the car travels once the brakes have been applied. Braking distance in m Speed of car in m/s Kinetic energy of car in kj (a) A student suggests, the braking distance is directly proportional to the kinetic energy. (i) Draw a line graph to test this suggestion. (3) Does the graph show that the student s suggestion was correct or incorrect? Give a reason for your answer..... () Page 8 of 54

9 (iii) Use your graph and the following equation to predict a braking distance for a speed of 35 metres per second (m/s). The mass of the car is 800 kilograms (kg). Show clearly how you obtain your answer. kinetic energy = ½ mv Braking distance =... m (iv) State one factor, apart from speed, which would increase the car s braking distance... () (b) The diagram shows a car before and during a crash test. The car hits the wall at 4 metres per second (m/s) and takes 0.25 seconds (s) to stop. (i) Write down the equation which links acceleration, change in velocity and time taken... () Calculate the deceleration of the car... Deceleration =... m/s 2 () (iii) In an accident the crumple zone at the front of a car collapses progressively. This increases the time it takes the car to stop. In a front end collision the injury to the car passengers should be reduced. Explain why. The answer has been started for you. By increasing the time it takes for the car to stop, the (Total marks) Page 9 of 54

10 Q7. A radioactive source emits alpha (α), beta (β) and gamma (γ) radiation. The diagram shows what happens to the radiation as it passes between two charged metal plates. (a) Which line P, Q or R shows the path taken by: (i) alpha radiation... gamma radiation?... () () (b) The diagram shows three different boxes and three radioactive sources. Each source emits only one type of radiation and is stored in a different box. The box reduces the amount of radiation getting into the air. Draw three lines to show which source should be stored in which box so that the minimum amount of radiation gets into the air. Page 0 of 54

11 (c) The graphs show how the count rates from three different radioactive sources, J, K, and L, change with time. (i) Which source, J, K, or L, has the highest count rate after 24 hours?... () For source L, what is the count rate after 5 hours?... counts per second (iii) Which source, J, K, or L, has the longest half-life?... () () (iv) A radioactive source has a half-life of 6 hours. What might this source be used for? Put a tick ( ) in the box next to your choice. To monitor the thickness of paper as it is made in a factory To inject into a person as a medical tracer To make a smoke alarm work () (Total 8 marks) Page of 54

12 Q8. A crane is used to lift a steel girder to the top of a high building. When it is lifted by the crane: the girder accelerates from rest to a speed of 0.6 m/s in the first 3 seconds; it then rises at a steady speed. (a) Calculate the acceleration of the girder. (Show your working.) (3) (b) (i) What is the weight of the steel girder? Answer... N () Calculate the power of the crane motor as it lifts the girder at a steady speed of 0.6 m/s. (Show your working. You can ignore the weight of the cable and hook which is small compared to the weight of the girder.) Answer... W Page 2 of 54

13 (c) A new motor is fitted to the crane. This motor accelerates the girder at 0.3 m/s 2. Calculate the force which the crane applies to the girder to produce this acceleration. (Show your working.) Answer... N (3) (Total 9 marks) Q9. The diagram shows part of the life cycle of a star which is much bigger than the Sun. (a) (i) What is the relationship between the masses of the dust and gas in the cloud in Stage 2 and the force of gravity between them? () Page 3 of 54

14 What is the relationship between the distance apart of the dust and gas in the cloud in Stage 2 and the force of gravity between them? () (b) In Stage 3 the star remains stable for millions of years. Explain why (c) What happens in Stage 4? (Total 6 marks) Q0. (a) Choose the best words from the box to complete the following sentences. billions fission friction fusion gases gravity liquids millions thousands (i) Stars form when enough dust and... from space are pulled together by.... Stars are able to give out energy for millions of years by the process of (iii)... The Sun is one of many... of stars in our galaxy. () () Page 4 of 54

15 (b) What is the name of our galaxy?... () (Total 5 marks) Q. The diagram shows a supermarket worker stacking jars of coffee onto a shelf. (a) The mass of each jar of coffee is 0.4 kg. Calculate the weight of each jar of coffee. gravitational field strength = 0 N/kg Write down the equation you use, and then show clearly how you work out your answer. Weight =... N Page 5 of 54

16 (b) The distance between the floor and the middle shelf is.2 m. Calculate the work done to lift one jar of coffee from the floor onto the shelf. Write down the equation you use, and then show clearly how you work out your answer and give the unit. Work done =... (3) (Total 5 marks) Q2. (a) A radioactive source emits alpha (α), beta (β) and gamma (γ) radiation. (i) Which two types of radiation will pass through a sheet of card?... () Which two types of radiation would be deflected by an electric field?... () (iii) Which type of radiation has the greatest range in air?... () (b) A student suggests that the radioactive source should be stored in a freezer at 20 C. The student thinks that this would reduce the radiation emitted from the source. Suggest why the student is wrong () Page 6 of 54

17 (c) Phosphorus-32 is a radioactive isotope that emits beta radiation. (i) How is an atom of phosphorus-32 different from an atom of the stable isotope phosphorus-3? () The graph shows how the count rate of a sample of phosphorus-32 changes with time. Use the graph to calculate the half-life of phosphorus-32. Show clearly how you used the graph to obtain your answer Half-life =... days Page 7 of 54

18 (iii) Plants use phosphorus compounds to grow. Watering the root system of a plant with a solution containing a phosphorus-32 compound can help scientists to understand the growth process. Explain why phosphorus-32 is suitable for use as a tracer in this situation (Total 9 marks) Page 8 of 54

19 Q3. The diagram shows the fuel gauge assembly in a car. The sliding contact touches a coil of wire and moves over it. The sliding contact and the coil form a variable resistor. The sliding contact is connected to a float via a pivot. The fuel gauge indicator is an ammeter. When the petrol level changes, the resistance of the circuit changes. This causes the pointer in the fuel gauge indicator to move. Page 9 of 54

20 (a) Use standard symbols to draw a circuit diagram for the fuel gauge assembly. (3) (b) How will the current in the circuit change as the level of petrol in the tank falls?... Explain the reason for your answer (Total 5 marks) Page 20 of 54

21 Q4. Our Sun is just one of many millions of stars in a galaxy called the Milky Way. Our Sun is in the main stable period of a star s lifetime. The massive force of gravity draws its matter together. This force is balanced by the very high temperatures, from the fusion of hydrogen atoms, which tend to make the Sun expand. Describe and explain what will happen to the Sun as the hydrogen is eventually used up (Total 3 marks) Q5. (a) The diagrams represent three atoms, X, Y and Z. Which of these atoms are isotopes of the same element? Give a reason for your answer. Page 2 of 54

22 (b) In a star, nuclei of atom X join to form nuclei of atom Y. Complete the sentences. The process by which nuclei join to form a larger nucleus is called nuclear.... This is the process by which a star releases.... (c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. A star goes through a lifecycle. Describe the lifecycle of a star like the Sun. (6) (Total 0 marks) Q6. The table shows how the count rate from a radioactive substance changes in 0 days. Time in days Count rate in counts per minute Page 22 of 54

23 (a) Draw a graph of count rate against time. The first two points have been plotted for you. (3) (b) (i) Use your graph to find out how long it takes for the count rate to fall from 880 counts per minute to 440 counts per minute. Time =... days () What is the half-life of this substance? Half-life =... days () Page 23 of 54

24 (c) The table gives the half-life and type of radiation given out by four different radioactive isotopes. Radioactive isotope Half-life in days Radiation given out bismuth beta polonium alpha and gamma radon alpha thorium beta and gamma Some samples of each isotope have the same count rate today. Which sample will have the lowest count rate one month from today?... Give a reason for your answer.... (Total 7 marks) Q7. (a) A chair lift carries two skiers, Greg and Jill, to the top of a ski slope. Greg weighs 700 N and Jill weighs 500 N. (i) Write down the equation that links distance moved, force applied and work done.... () Page 24 of 54

25 Calculate the work done to lift Greg and Jill through a vertical height of 200 m. Show clearly how you work out your answer and give the unit work done =... (3) (b) The chair takes 5 minutes to move from the bottom to the top of the ski slope. Use the following equation to calculate the power required to lift Greg and Jill to the top of the ski slope. Show clearly how you work out your answer. power = power =... watts (c) The chair lift is driven by an electric motor. (i) Why would the power output of the electric motor need to be larger than your answer to part (b)? () Complete the following sentence. When the ski lift is working... energy supplied to the motor is usefully transferred as gravitational... energy. () (Total 8 marks) Page 25 of 54

26 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) (b) 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 26 of 54

27 Q9. (a) The table gives information about the radioactive isotope, radon-222. mass number 222 atomic number 86 radiation emitted alpha particle (i) Complete the following sentence. The mass number is the total number of... and... inside an atom. Radon-222 is an isotope of radon. How many protons are there in an atom of radon-222?... () (iii) When an atom of radon-222 emits an alpha particle, the radon-222 changes into an atom of polonium-28. An alpha particle consists of 2 protons and 2 neutrons. How is the structure of the nucleus of a polonium-28 atom different from the structure of the nucleus of a radon-222 atom?.. () Page 27 of 54

28 (b) The pie chart shows the average radiation dose that a person in the UK receives each year from natural background radiation. The doses are measured in millisieverts (msv). (i) Calculate the proportion of natural background radiation that comes from radon. Show clearly how you work out your answer..... Proportion of radon =... Not all background radiation is from natural sources. Name one source of background radiation that is not natural... () Page 28 of 54

29 (c) The bar chart shows the average yearly dose from natural background radiation in different European countries. (i) How many times bigger is the average annual background dose in Germany compared to the UK?.. () The following table gives the effects of different radiation doses on the human body. Radiation dose in msv Effects Immediate illness; death within a few weeks 000 Radiation sickness; unlikely to cause death 50 Lowest dose with evidence of causing cancer A family goes to Germany for a two-week holiday. Should they be concerned about the higher level of background radiation in Germany? Draw a ring around your answer. Yes No Explain your answer (Total 0 marks) Page 29 of 54

30 Q20. (a) The diagram shows the circuit used by a student to measure the power of a filament lamp. Name a component connected in parallel with the filament lamp.... () (b) By adding another component to the circuit, the student is able to obtain a range of ammeter and voltmeter readings. Ammeter reading in amps Voltmeter reading in volts (i) Which one of the following components did the student add to the circuit? Draw a ring around your answer. fuse switch variable resistor () What is the range of ammeter readings taken by the student? from... amps to... amps () Page 30 of 54

31 (iii) Use the data in the table and the equation in the box to calculate the maximum power of the filament lamp. Show clearly how you work out your answer Power =... W (3) (c) Complete the following sentence by drawing a ring around the correct line in the box. increases As the temperature of a filament lamp increases, its resistance remains constant decreases () (Total 7 marks) Page 3 of 54

32 Q2. (a) The graphs, A, B and C, show how the current through a component varies with the potential difference (p.d.) across the component. Draw a line to link each graph to the correct component. Draw only three lines. (b) Each of the circuits, J, K and L, include two diodes. In which one of the circuits, J, K or L, would the filament lamp be on?... () (Total 3 marks) Page 32 of 54

33 Q22. 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 (b) 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 33 of 54

34 Q23. (a) A student rubs a nylon comb on the sleeve of his jumper. (i) Use words from the box to complete the following sentence. electrons hand jumper protons The comb becomes negatively charged because... move from the student s... to the comb. What type of charge is left on the jumper?... () (iii) The negatively charged comb is placed close to a charged plastic ruler. The comb and the ruler attract each other. Complete the following sentence by drawing a ring around the correct line in the box. negatively charged The ruler is positively charged uncharged () Page 34 of 54

35 (b) Electrostatic charge can damage computer chips. People working with computer chips may wear a special bracelet, with a wire joining the bracelet to earth (the earth wire). Any negative charge on the person will flow through the wire to earth. (i) Which one of the following materials should the bracelet be made from? Draw a ring around your answer. copper plastic rubber Give a reason for your answer..... Which one of the following words is used to describe the rate of flow of charge through a wire? Draw a ring around your answer. current resistance voltage () (Total 7 marks) Page 35 of 54

36 M. mark for each line if more than line is drawn from a graph in List A then all those lines are marked incorrect [3] M2. (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 (b) 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 Page 36 of 54

37 (c) 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 [] M3. (a) (mass of) positive charge (b) three lines correct (c) allow mark for correct line if more than line is drawn from a box in List A then all those lines are incorrect new scientific evidence / data is obtained 2 which cannot be explained by the model [5] Page 37 of 54

38 M4. (a) Particle Relative Mass Relative charge Proton Neutron 0 (b) accept one, accept + do not accept accept zero do not accept no charge/ nothing/neutral unless given with 0 equal numbers/amounts of protons and electrons protons and electrons have equal but opposite charge accept protons charge + and electron charge accept (charge) on proton cancels/balances (charge) on electron accept positive (charges) cancel out the negative(charges) neutrons have no charge is neutral do not accept total charge of protons, electrons (and neutrons) is 0 unless qualified (c) (i) (3) fewer neutrons accept lower/ smaller mass number do not accept different numbers of neutrons any mention of fewer/more protons/electrons negates mark accept answers in terms of U-238 providing U-238 is specifically stated i.e. U-238 has (3) more neutrons neutron (iii) (nuclear) fission accept fision do not accept any spelling that may be taken as fusion [7] Page 38 of 54

39 M5. (a) plastic accept rubber as it is a good electrical insulator accept as it is a poor electrical conductor any mention of heat negates this mark copper as it is a good electrical conductor any mention of heat negates this mark (b) all ticks and crosses in the correct places A B C D allow mark for 3 correct 2 [6] M6. (a) (i) linear scales used do not credit if less than half paper used points plotted correctly all of paper used (straight) line of best fit drawn allow a tolerance of half square correct and straight line through origin all needed e.c.f. if their (a)(i) is straight but not through the origin - incorrect because line does not go through origin credit a calculation that shows proportionality (iii) 62 ± 0.5 (m) credit mark for KE = or 490kJ credit mark for correct use of graph clearly shown 2 Page 39 of 54

40 (iv) any one from: wet or icy or worn or smooth road accept slippery slope brakes worn accept faulty brakes car heavily loaded worn tyres downhill slope do not accept anything to do with thinking distance e.g. driver tired or drunk (b) (i) acceleration = accept correct transformation accept accept m/s = 2 do not accept acceleration = 56 accept 56 (iii) deceleration is reduced accept deceleration is slower accept acceleration force on car and or passengers is reduced accept an answer in terms of change in momentum for full credit [] M7. (a) (i) P Q Page 40 of 54

41 (b) 3 lines correct allow mark for correct line two lines drawn from any source or box both incorrect 2 (c) (i) K 56 accept inclusive (iii) K (iv) to inject... tracer [8] M8. (a) *evidence of acceleration = or gains mark but 0.2 gains 2 marks units m/s 2 for mark 3 (b) (i) 2000 or 960 for mark evidence of power = or weight speed (credit figures)/ (iii) gains mark but 200/76 or figure consistent with (b)(i) gains 2 marks 2 Page 4 of 54

42 (c) evidence of force = mass acceleration or gains mark but 60 gains 2 marks but 60 + weight of girder (2060/2020*) (or figure consistent with (b)(i)) gains 3 marks 3 [9] M9. (a) (i) the bigger the masses (of the dust and gases then) the bigger the force / gravity (between them) accept the converse the greater the distance (between the dust and gases then) the smaller the force / gravity (between them) accept the converse (b) radiation pressure and gravity / gravitational attraction these are balanced / in equilibrium must be in correct context do not accept are equal or there is sufficient / a lot of hydrogen / fuel to last a very long time second mark consequent on first (c) any two from: hydrogen runs out / is used up nuclei larger than helium nuclei formed accept bigger atoms are formed however do not accept any specific mention of an atom with a mass greater than that of iron (star expands to) / become(s) a red giant 2 [6] Page 42 of 54

43 M0. (a) (i) gases () (iii) gravity () correct order essential for credit fusion billions 2 (b) Milky Way u.c. initials not essential [5] M. (a) 4 (N) allow mark for correct substitution into correct equation ie (b) 4.8 their (a).2 correctly calculated gains 2 marks allow mark for substitution into correct equation ie 4.2 or their (a)(i).2 2 joule or J [5] M2. (a) (i) beta and gamma both answers required accept correct symbols alpha and beta both answers required accept correct symbols (iii) gamma accept correct symbol Page 43 of 54

44 (b) nothing (you do to a radioactive substance / source) changes the count rate / activity / rate of decay / radiation (emitted) accept it = radiation emitted or (reducing) the temperature does not change the activity / count rate / rate of decay / radiation (emitted) (c) (i) has one more neutron correct answer only (iii) 4 days no tolerance allow mark for showing a correct method on the graph any two from: beta particles / radiation can be detected externally beta particles / radiation can pass out of / through the plant long half-life gives time for phosphorus to move through the plant / be detected / get results phosphorus-32 is chemically identical to phosphorus-3 2 phosphorus-32 is used in the same way by a plant as phosphorus-3 2 [9] M3. (a) 3 one mark for each symbol allow more than 2 cells joined max. 2 marks if symbols incorrectly allow rheostat arrow in either direction Page 44 of 54

45 (b) current will decrease since resistance greater [5] M4. any three from max 2 if stages but no explanation the star (Sun) expands because (inward) gravitational forces no longer balance (outward) force accept the star collapses rapidly causing the core temperature to increase and the star to expand accept it expands because the forces are unbalanced to become a red giant when the fusion stops it contracts / cools accept (when hydrogen is used up) it collapses under gravity accept when fusion stops it contracts and explodes to become a white dwarf accept to become a supernova / pulsar / neutron star / black hole (only if red giant has exploded) [3] M5. (a) Y and Z both required, either order same number of protons (b) fusion energy correct order only Page 45 of 54

46 (c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. No relevant content. There is a brief description of the life cycle of a star like the sun. There is some description of the life cycle of a star like the sun. There is a clear and detailed description of the life cycle of a star like the sun. 0 marks Level ( 2 marks) Level 2 (3 4 marks) Level 3 (5 6 marks) examples of the physics points made in the response to score full marks either the term red giant or white dwarf must be used gases and dust pulled together by gravity nuclear fusion begins when forces are balanced star is stable expands cools becomes a red giant do not accept red supergiant shrinks temperature rises glows much brighter becomes a white dwarf any mention of supernova negates a mark any mention of black hole negates a mark individual points must be linked in a correct sequence [0] M6. (a) all points correctly plotted tolerance ± square on y axis only allow mark for 3 correctly plotted points attempt made to draw a smooth curve do not accept dot-to-dot line 2 Page 46 of 54

47 (b) (i) 3 days 0.2 or any value correctly obtained using their graph line if no line drawn in (a), answer must be exactly 3 3 days or their (b)(i) (c) radon-222 accept radon or 222 accept alpha or 3.8 correct isotope required for reason to score has the shortest half-life accept the others have longer half-lives [7] M7. (a) (i) work (done) = force (applied) distance (moved) accept W = F s or W = F d accept provided subsequent method is correct allow mark for correct substitution or correct use of 200 (N) joules accept J do not accept j / Nm 2 (b) 800 (watts) accept 0.8 kw accept their (a) 300 correctly evaluated for 2 marks allow mark for correct substitution (a) 5 correctly evaluated for mark 2 Page 47 of 54

48 (c) (i) any one from: needs to raise the chair / lift lifting more than one chair allow lifting more than 2 people implication of a heavier weight energy transfer to the surroundings correctly qualified accept loss for transfer do not accept motor inefficient do not accept motor gets hot do not accept friction unless the location is specified as external to the motor electrical accept electric potential both answers required for the mark [8] 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) 3 (b) allow mark for correct substitution into the correct equation ie / [5] M9. (a) (i) protons neutrons answers may be in either order 86 Page 48 of 54

49 (iii) two fewer protons and two fewer neutrons do not accept two fewer protons and neutrons or 84 protons 34 neutrons do not accept 28 protons and neutrons (b) (i) 0.4 accept / accept 40 % for 2 marks allow mark for correct totalling =.8 allow mark for a clearly correct method with a clearly incorrect total 2 any one from: nuclear weapon testing do not accept nuclear nuclear power (stations) accept nuclear/ radioactive waste nuclear accidents medical accept X-rays (c) (i) 2 accept 2: accept twice as big ignore units Page 49 of 54

50 No with a reasonable reason explained only going for two weeks so or even staying for a year total exposure well under lowest limit for causing cancer mark is for a time frame mark is for correctly relating to a dose or Yes with a reasonable reason explained all levels of radiation are (potentially) hazardous () accept low doses could still cause cancer accept all levels affect you do not accept radiation dose is high(er) do not accept level of background radiation is higher in Germany harm caused by lower doses may not have been recorded () or evidence may not be complete or insufficient research into effect of small doses [0] M20. (a) voltmeter and no other do not accept voltage (b) (i) variable resistor accept accept accept (iii) 3.3 (W) allow mark for correct data choice allow 2 marks for substitution of correct data i.e the following answers gain 2 marks 0.0 / 0.30 / 0.80 /.75 allow mark for substitution of incorrect of data incorrectly calculated e.g = 0.6 scores mark 3 Page 50 of 54

51 (c) increases [7] M2. (a) three lines drawn correctly allow mark for correct line if more than one line goes from a graph, both are incorrect 2 (b) J [3] Page 5 of 54

52 M22. (a) alternates accept switches accept (constantly) changes accept goes up and down between positive and negative (b) 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] M23. (a) (i) electrons jumper positive accept protons accept + (iii) positively charged accept any clear way of indicating the answer (b) (i) copper it is an (electrical) conductor only accept if copper is identified do not accept it conducts heat accept it conducts heat and electricity accept copper is the best conductor accept correct description of conduction Page 52 of 54

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