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Transcript
M1.(a) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a ‘best-fit’ approach to the marking. 0 marks No relevant / correct content. Level 1 (1–2 marks) Either there is an attempt at a description of the construction of a transformer or a correct statement of the effect of one type of transformer on the input p.d. Level 2 (3–4 marks) There is a description of the construction of a transformer and a correct statement of the effect of one type of transformer on the input p.d. Level 3 (5–6 marks) There is a clear description of the construction of a transformer and there is a correct description of how transformers affect the input p.d. details of construction: extra information a (laminated) core core is made from a magnetic material / iron 2 coils the coils are made from an electrical conductor / copper the coils are covered in plastic / insulation the coils are (usually) on opposite sides step-up transformer has more turns on secondary coil than (its) primary (or vice versa) step-down transformer has fewer turns on secondary coil than (its) primary (or vice versa) effect on input p.d. : step-up transformer, the output p.d. is greater (than the input p.d.) accept voltage for p.d. step-down transformer, the output p.d. is lower (than the input p.d.) 6 (b) switch mode (transformer) 1 [7] M2. 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. 0 marks There is a brief explanation of how a current is caused to flow in the starter motor circuit. Level 1 (1–2 marks) There is some explanation of how a current is caused to flow in the starter motor circuit. Level 2 (3–4 marks) There is a clear and detailed explanation of how a current is caused to flow in the starter motor circuit. Level 3 (5–6 marks) examples of the physics points made in the response current flows through the coil / electromagnet magnetic field produced accept electromagnet switches on (short side of) iron bar attracted to electromagnet contacts pushed together (by iron bar) starter motor circuit completed current flows through starter motor or p.d. across starter motor [6] M3. (a) so the results can be compared fairly fair test is insufficient 1 (b) J L M all 3 required and no other 1 (c) (i) for a given current the number of paper clips increases by the same factor as the number of turns 1 plus a mathematical explanation using the data eg a current of 1 A with 10 turns picks up 3 clips, a current of 1 A with 20 turns picks up 6 clips 1 (ii) 30 allow 1 mark for showing correct use of figures eg 20 turns × 5 = 100 turns 2 (iii) check the new data / repeat the experiment 1 to identify any anomalous results 1 then reconsider prediction / hypothesis in the light of new evidence 1 [9] M4. (a) (i) arrow from centre of the ball and at right angles to the string and in the correct direction arrow should point to the student’s belt accept free-hand ‘straight’ line do not accept curved line 1 (ii) increase accept ‘be stronger / bigger’ 1 increase accept ‘be stronger / bigger’ 1 increase accept ‘be stronger / bigger’ 1 (b) speed velocity direction all three correct any two correct for 1 mark otherwise 0 marks 2 (c) (i) centripetal accept ‘centripedal’ and other minor misspellings do not accept anything which could be ‘centrifugal’ 1 (ii) gravity accept ‘weight’ accept ‘force of attraction due to mass(es) (of the Moon and the Earth)’ 1 (iii) electron(s) 1 (iv) electrostatic accept ‘electrical’ do not accept just ‘centripetal’ 1 [10] M5. (i) accept input for primary accept output for secondary accept or correct transposition 1 (ii) 60 allow 1 mark for correct transformation 2 [3] M6.(a) hydraulic (system) 1 (b) 15.40 ×102 or 1540 allow 1 mark for correct substitution, ie 8.75 × 104 = or 87 500 = or F = 8.75 × 104 × 1.76 ×10-2 or F = 87 500 × 0.0176 2 (c) any one environmental advantage: stating a converse statement is insufficient, or a disadvantage of the usual oil, ie the usual oil is nonrenewable plant oil is renewable using plant oil will conserve (limited) supplies or extend lifetime of the usual / crude oil. plant oil releases less carbon dioxide (when it is being produced / processed) plant oil will add less carbon dioxide to the atmosphere (when it is being produced / processed, than the usual oil) plant oil removes carbon dioxide from or adds oxygen to the air when it is growing stating that plant oil is carbon neutral is insufficient 1 (d) (the current flowing through the coil) creates a magnetic field (around the coil) 1 (this magnetic field) interacts with the permanent magnetic field or current carrying conductor is in a (permanent) magnetic field it must be clear which magnetic field is which 1 this produces a (resultant) force (and coil / cone moves) 1 when the direction of the current changes, the direction of the force changes to the opposite direction accept for 2 marks the magnetic field of the coil interacts with the permanent magnetic field 1 [8] M7.(a) centripetal (force) allow tension (between astronaut and seatbelt) 1 towards the centre (of the G-machine / circle) do not accept towards the centre of the Earth allow inwards 1 (b) (i) the greater the speed (of a centrifuge), the greater the force answers must be comparative accept velocity for speed accept positive correlation between speed and force speed and force are not proportional – treat as neutral 1 the smaller the radius, the greater the force (at a given speed) allow (G machine) 1 has / produces a greater force (than G machine 2 ) at the same speed must be comparative, eg a small radius produces a large force = 0 marks on own 1 as the speed increases the rate of change in force increases accept force is proportional to the square of the speed or doubling speed, quadruples the force accept any clearly correct conclusion 1 (ii) 12000 (N) or 12 k(N) 1 (c) (i) the current (in the coil) creates a magnetic field (around the coil) accept the coil is an electromagnet 1 so the magnetic field of the coil interacts with the (permanent) magnetic field of the magnets (producing a force) accept the two magnetic fields interact (producing a force) if no marks scored an answer in terms of current is perpendicular to the (permanent) magnetic field is worth max 1 mark 1 (ii) vertically downwards arrow on side A one arrow insufficient and vertically upwards arrow on side C 1 (iii) the current is parallel to the magnetic field allow the current and magnetic field are in the same direction allow it / the wire is parallel to the magnetic field 1 (d) increase the current / p.d. (of the coil) accept decrease resistance accept voltage for p.d. accept increase strength of magnetic field / electromagnet 1 (e) yes with suitable reasonorno with suitable reason eg yes – it has increased our knowledge yes – It has led to more (rapid) developments / discoveries (in technology / materials / transport) accept specific examples no – the money would have been better spent elsewhere on such things as hospitals (must quote where, other things not enough) no mark for just yes / no reason must match yes / no 1 [12]