Cambridge IGCSE Physics 0625 — 2015 May/June Paper 2 · Variant 3

This document consists of 19 printed pages and 1 blank page. DC (CW/CGW) 90391/2 © UCLES 2015 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 4 6 6 9 9 6 0 8 7 0 * PHYSICS 0625/23 Paper 2 Core May/June 2015 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. Take the weight of 1 kg to be 10 N (i.e. acceleration of free fall = 10 m / s2). At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.

2 0625/23/M/J/15 © UCLES 2015 1 In the past, burning candles were used as timers. A boy carries out an experiment to make his own timer using a burning candle. Fig. 1.1 shows the length of the candle, and the clock he used, at the start of the experiment and at the end of the experiment. start of the experiment end of the experiment 11: 50 5.0 cm 3.2 cm candle at the start candle at the end 14 : 05 clock clock Fig. 1.1 (not to scale) (a) The candle has a cross-sectional area of 1.6 cm2. Calculate the volume of candle at the start of the experiment. volume = … cm3 [2] (b) Use Fig. 1.1 to complete the table. time at start of the experiment time at end of the experiment time for which the candle was burning … hours …minutes = … hours [2]

3 0625/23/M/J/15 © UCLES 2015 [Turn over (c) The difference in the length of the candle from the start to the end of the experiment was 1.8 cm. Calculate the rate, in cm / hour, at which the candle burns. rate = … cm / hour [2] (d) The boy estimates that he would need a candle about 24 cm long, of the same material and diameter, to make a candle timer that would last at least one day. State whether the boy’s estimate is correct. Give a reason for your answer. … … …[2] [Total: 8]

4 0625/23/M/J/15 © UCLES 2015 2 (a) A student is asked to find the density of a small block of metal, as shown in Fig. 2.1. length width height Fig. 2.1 Use words from the list below to complete the following sentences. balance beaker measuring cylinder protractor rule thermometer (i) The student should use a … to measure the length, width and height of the metal block. (ii) The student should use a … to find the mass of the metal block. [2] (b) A jeweller has a small block of metal. The block has a mass of 15.2 g and a volume of 1.36 cm3. (i) Calculate the density of the metal. density = … g / cm3 [3] (ii) The jeweller looks up the values for the density of various metals and produces a table, part of which is shown below. metal density g / cm3 gold 19.3 lead 11.3 platinum 21.5 silver 10.5 Using your answer to (b)(i) and the information in the table, state which metal the block is most likely to be made from. …[1] [Total: 6]

5 0625/23/M/J/15 © UCLES 2015 [Turn over 3 In the columns below are physical quantities and the units in which they are measured. Draw a line from each quantity to its corresponding unit. One line is drawn for you. quantity unit energy °C resistance m / s speed J temperature Ω [Total: 2]

6 0625/23/M/J/15 © UCLES 2015 4 A toy car is rolling down a slope. Fig. 4.1 shows the total forward force and the total backward force acting on the car. 16 N 12 N Fig. 4.1 (a) Calculate the resultant force on the car. size of force = …N direction of force = … [2] (b) What will be the effect of this resultant force on the car’s motion? … …[2] [Total: 4]

7 0625/23/M/J/15 © UCLES 2015 [Turn over 5 A girl cycles to meet a friend. The distance-time graph for her journey from start to finish is shown in Fig. 5.1. 0 200 400 600 800 1000 1200 0 1 2 3 time / minutes distance / m 4 5 A B C D E Fig. 5.1 (a) How far does the girl travel from start to finish? distance = …[1] (b) Describe the motion of the girl between points B and C. …[1] (c) Which section of the graph shows (i) the part of the girl’s journey that involves cycling up a hill 500 m long, between … and … [1] (ii) the girl travelling at the fastest speed? between … and … [1] (d) Calculate her average speed, in m / s, for the whole journey. average speed = … m / s [3] [Total: 7]

8 0625/23/M/J/15 © UCLES 2015 6 Different types of power station use different sources of energy. (a) Draw one straight line from each energy source to the type of power station that uses it. energy source type of power station fossil fuel hot rocks underground uranium fuel rods hydroelectric nuclear geothermal coal-fired wind farm [3]

9 0625/23/M/J/15 © UCLES 2015 [Turn over (b) Fig. 6.1 shows part of a solar power station. PLUURU SLSHFDUU\LQJ ZDWHU Fig. 6.1 These are some of the stages explaining how the power station works. They are not in the correct order. A Electricity is generated. B The turbine turns the generator. C Steam drives the turbine. D Water in the pipe absorbs energy. Use the letters A, B, C and D to complete the flow chart to explain how the power station works. Radiation from the Sun hits the mirror. Radiation is reflected onto the pipe. Hot water turns into steam. [3] [Total: 6]

10 0625/23/M/J/15 © UCLES 2015 7 (a) The arrows on Fig. 7.1 represent four changes of state. solid liquid gas Fig. 7.1 On each arrow, write the name for the change of state. [3] (b) The statements below are about particles in a gas. Tick three boxes to show which statements are correct. The particles move randomly. The particles are in a regular repeating pattern. The particles are much further apart than they are in a solid. The particles vibrate about fixed positions. The particles expand when they are heated. The particles move faster when they are heated. [3] (c) A student spills a small amount of nail varnish remover on one of her hands. Nail varnish remover is a liquid with a low boiling point. Explain why this hand feels colder than her other hand. … … … …[3] [Total: 9]

11 0625/23/M/J/15 © UCLES 2015 [Turn over 8 A student looks into a vertical mirror to see the reflection of a burning candle. Fig. 8.1 shows one ray of light being reflected by the mirror. candle flame mirror eye Fig. 8.1 (a) On the ray in Fig. 8.1, mark arrows to indicate the direction of travel of the light. [1] (b) On Fig. 8.1, carefully mark the position of the image of the candle flame. [2] (c) The candle is moved further from the mirror. State what, if anything, happens to (i) the position of the image … (ii) the size of the image. … [2] [Total: 5]

12 0625/23/M/J/15 © UCLES 2015 9 (a) Fig. 9.1 represents a wave in a water tank. Five distances are shown, labelled A, B, C, D and E. A C B D E Fig. 9.1 (i) 1. Which property of the wave is represented by distance C? …[1] 2. Which of the labelled distances represents the wavelength of the wave? …[1] (ii) Water waves are transverse waves. State another example of a transverse wave. …[1] (iii) The speed of the wavefronts is 7.5 cm / s. Calculate the distance moved by a wavefront in 4.0 s. distance = … cm [2]

13 0625/23/M/J/15 © UCLES 2015 [Turn over (b) Fig. 9.2 shows, from above, a wave travelling on water. shallow water wavefront direction of travel of wave water tank deep water Fig. 9.2 The wave has reached an area of shallow water, where it travels more slowly. (i) Complete the diagram to show the wavefronts in the shallow water. [3] (ii) State the term used to describe what happens to the wave as it enters the shallow water. …[1] [Total: 9]

14 0625/23/M/J/15 © UCLES 2015 10 A student is investigating static electricity. (i) The student charges a plastic rod by rubbing it with a dry cloth. The rod becomes positively charged as shown in Fig. 10.1. + + + + + + + + + + + + + + + cloth rod Fig. 10.1 1. State the sign of the charge, if any, on the cloth. …[1] 2. State which particles the cloth has gained for it to have this charge. …[1] (ii) The student then rubs two thin plastic strips with another dry cloth. The strips are suspended so that they are free to move. Fig. 10.2 shows the two plastic strips before and after the student rubs them with the dry cloth. before rubbing after rubbing sticky tape string string plastic strips Fig. 10.2 Explain why the bottom ends of the strips move apart after rubbing. … …[2]

15 0625/23/M/J/15 © UCLES 2015 [Turn over (iii) A boy wears a shirt made from nylon. After wearing the shirt for some time he finds the shirt clinging to his body. Use your knowledge of electrostatic charges to explain why this occurs. … … …[2] [Total: 6]

16 0625/23/M/J/15 © UCLES 2015 11 Some cars have electrically heated front seats. Each seat has a warm and a hot setting, controlled by a switch. The circuit for one seat is shown in Fig. 11.1. 12.0 V heater switch fuse A B C X Fig. 11.1 (a) The circuit contains a switch that can connect to any of the contacts A, B or C. In the table below, put one tick for each switch setting to indicate the condition of the seat. condition of seat switch setting off warm hot A B C [3] (b) When the heater setting is on ‘hot’, the current in the heater is 6.0 A. The potential difference across the heater is 10.0 V. Calculate the resistance of the heater. resistance = … [3]

17 0625/23/M/J/15 © UCLES 2015 [Turn over (c) What is the name and purpose of component X? name of component … purpose … … [2] (d) The heated seat develops a fault and there is a large current in the circuit. Explain what happens to prevent further damage to the circuit. … … …[2] [Total: 10]

18 0625/23/M/J/15 © UCLES 2015 12 Fig. 12.1 represents an atom of carbon. neutron X Y Fig. 12.1 (not to scale) (a) (i) State the name of particle X. …[1] (ii) State the name of particle Y. …[1] (b) Carbon-14 is unstable. It decays by beta emission to form nitrogen. Complete the equation for this decay. 14 6C … …N + 0 –1e [2]

19 0625/23/M/J/15 © UCLES 2015 (c) The half-life of carbon-14 is 5800 years. A piece of wood contained 20 000 carbon-14 atoms when it was buried in a landslide. Calculate the number of years it takes until the number of carbon-14 atoms in the wood is 2500. number of years = … [4] [Total: 8]

20 0625/23/M/J/15 © UCLES 2015 BLANK PAGE Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the May/June 2015 series 0625 PHYSICS 0625/23 Paper 2 (Core Theory), maximum raw mark 80 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2015 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 NOTES ABOUT MARK SCHEME SYMBOLS & OTHER MATTERS B marks are independent marks, which do not depend on any other marks. For a B mark to be scored, the point to which it refers must actually be seen in the candidate's answer. M marks are method marks upon which accuracy marks (A marks) later depend. For an M mark to be scored, the point to which it refers must be seen in a candidate's answer. If a candidate fails to score a particular M mark, then none of the dependent A marks can be scored. C marks are compensatory method marks which can be scored even if the points to which they refer are not written down by the candidate, provided subsequent working gives evidence that they must have known it. For example, if an equation carries a C mark and the candidate does not write down the actual equation but does correct working which shows he knew the equation, then the C mark is scored. A marks are accuracy or answer marks which either depend on an M mark, or which are one of the ways which allow a C mark to be scored. Brackets ( ) around words or units in the mark scheme are intended to indicate wording used to clarify the mark scheme, but the marks do not depend on seeing the words or units in brackets, e.g. 10 (J) means that the mark is scored for 10, regardless of the unit given. c.a.o. means “correct answer only”. e.c.f. means “error carried forward”. This indicates that if a candidate has made an earlier mistake and has carried his incorrect value forward to subsequent stages of working, he may be given marks indicated by e.c.f. provided his subsequent working is correct, bearing in mind his earlier mistake. This prevents a candidate being penalised more than once for a particular mistake, but only applies to marks annotated “e.c.f.” e.e.o.o. means “each error or omission”. Underlining indicates that this must be seen in the answer offered, or something very similar. OR / or indicates alternative answers, any one of which is satisfactory for scoring the marks. AND indicates that both answers are required to score the mark. Spelling Be generous with spelling and use of English. However, do not allow ambiguities e.g. spelling which suggests confusion between reflection/refraction/diffraction or thermistor/transistor/transformer. Sig. figs. On this paper, answers are generally acceptable to any number of significant figures ≥2, except where the mark scheme specifies otherwise or gives an answer to only 1 significant figure. Units On this paper, incorrect units are not penalised, except where specified. More commonly, marks are awarded for specific units. Fractions Fractions are only acceptable where specified.

Page 3 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 Extras If a candidate gives more answers than required, irrelevant extras are ignored; for extras which contradict an otherwise correct response, or are forbidden by the mark scheme, use right plus wrong = 0. Ignore indicates that something which is not correct is disregarded and does not cause a right plus wrong penalty. NOT indicates that an incorrect answer is not to be disregarded, but cancels another otherwise correct alternative offered by the candidate i.e. right plus wrong penalty applies.

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 1 (a) volume = length × cross-sectional area words, symbols or numbers C1 8.0 accept 8 (cm3 ) A1 (b) time of burning: 2 hours 15 minutes B1 2.25 hours, accept 2¼ hours B1 (c) (speed = ) distance ÷time in any form: symbols, words, numbers, ecf from (b) C1 0.8(0) cm / hour, ecf from (b) A1 (d) correct deduction from candidate’s (c) B1 correct reasoning from candidate’s (c) e.g. 24 cm candle would burn for 30 h OR 19.2 cm will burn in 24 h B1 [Total: 8] 2 (a) (i) rule(r) A1 (ii) balance A1 (b) (i) (density =) mass ÷ volume in any form: symbols, words, numbers C1 15.2 ÷ 1.36 C1 11.2 (g / cm3) accept 11 A1 (ii) lead, ecf from (b) (i) B1 [Total: 6] 3 max. B2 note: 1 mark for 1 or 2 lines correct, 2 marks for all 3 lines correct ° C energy m / s J Ω resistance speed temperature

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 4 (a) 4 (N) B1 up the slope B1 (b) idea of changes speed C1 reduces speed / slows down / decelerates / retardation A1 [Total: 4] 5 (a) 1100 (m) ± 20 B1 (b) stationary / not moving / at rest B1 (c) (i) C AND D B1 (ii) D AND E B1 (d) (speed=) distance ÷ time, in any form: symbols, words, numbers, ecf from (a) C1 use of 300 s OR conversion of time to s OR ÷ 60 C1 3.7 OR 3.67 (m / s) A1 [Total: 7] 6 (a) line from fossil fuel to coal-fired B1 line from hot rocks underground to geothermal B1 line from uranium fuel rods to nuclear B1 (b) D, C, B, A max. B3 note: all correct order = 3 marks, 2 or 3 correct = 2 marks, 1 correct = 1 mark [Total: 6] 7 (a) melting evaporating / boiling max. B3 freezing / solidification condensing note: 3 marks for all 4 correct, 2 marks for 3 correct, 1 mark for 2 correct

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 (b) tick in first box (particles move randomly) B1 tick in third box (particles are much further apart...) B1 tick in sixth box (particles move faster...) B1 (c) any three from: max. B3 • nail varnish remover evaporates • energy needed to evaporate / most energetic particles escape • energy is transferred from student / heat flow gives sensation of cold • remaining liquid colder / average KE is less [Total: 9] 8 (a) arrow from candle to mirror OR from mirror to eye B1 NOT contradictions (b) candle flame image drawn at same height as flame B1 candle flame image drawn same distance behind mirror as flame is in front B1 (c) (i) further away (from mirror / eye) B1 (ii) same (size) / nothing / does not change B1 [Total: 5] 9 (a) (i) 1. amplitude B1 2. D B1 (ii) any named example of electromagnetic wave OR seismic ‘S’ wave B1 (iii) speed = distance÷time OR 7.5 × 4.0 OR speed × time C1 30 (cm) A1 (b) (i) at least one straight line in shallow water and at different angle, accept refracted wrong way B1 line(s) show wave refraction away from normal B1 at least 3 lines drawn showing refracted wave of constant wavelength, different from incident wavelength, and continuous with incident wavefronts B1 (ii) refraction B1 [Total: 9]

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 10 (i) 1. negative B1 2. electrons B1 (ii) (both) strips have same (type of) charge B1 (and so) repel (each other) B1 (iii) (idea of) shirt gaining / losing (electric) charge OR becomes charged OR charge transferred between shirt and body B1 unlike charges attract B1 [Total: 6] 11 (a) A: warm ticked B1 B: off ticked B1 C: hot ticked B1 (b) V=I×R in any form OR V ÷ I C1 (R = ) 10 ÷ 6.0 C1 1.7 OR 1.67 (Ω) A1 accept 1.66 1.6 scores 2 marks (c) lamp B1 to indicate heater is on / working B1 (d) any two from: max. B2 • fuse identified as the relevant component • the fuse will melt / blow / break • (this) breaks circuit / stops current [Total: 10] 12 (a) (i) proton B1 (ii) electron B1 (b) nucleon number = 14 B1 proton number = 7 B1

Page 8 Mark Scheme Syllabus Paper Cambridge IGCSE – May/June 2015 0625 23 © Cambridge International Examinations 2015 (c) evidence of halving 20 000 C1 idea of three half lives C1 3 × 5800 allow ecf for candidate’s no. of ½ lives C1 17 400 (years) A1 [Total: 8]