Cambridge IGCSE Physics 0625 — 2014 Oct/Nov Paper 2 · Variant 2

This document consists of 15 printed pages and 1 blank page. DC (AC/SW) 81803/5 © UCLES 2014 [Turn over Cambridge International Examinations Cambridge International General Certificate of Secondary Education * 0 7 5 6 6 7 2 3 4 7 * PHYSICS 0625/22 Paper 2 Core October/November 2014 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 0625/22/O/N/14 © UCLES 2014 1 (a) Which two conditions apply for an object on Earth to be in equilibrium? Tick two boxes. there are no forces acting on the object the object has no mass there is no resultant force on the object there is no resultant moment [2] (b) Fig. 1.1 is a simplified diagram of a balance with equal arms. Fig. 1.1 A copper block of unknown mass is placed on the left-hand pan. Six standard masses, placed on the right-hand pan, cause the balance to be in equilibrium, with the beam horizontal. The six standard masses on the right-hand pan are: 100 g, 100 g, 50 g, 10 g, 5 g, 2 g (i) What is the mass of the copper block? mass = … g [1] (ii) What will be seen to happen if the 2 g mass is removed from the right-hand pan? … …[1] (iii) The volume of the copper block is 30 cm3. Calculate the density of copper. State the unit in your answer. density = … [4] [Total: 8]

3 0625/22/O/N/14 © UCLES 2014 [Turn over 2 A car travels along a straight, horizontal road at a steady speed of 36 m / s. The total resistive force on the car is 2800 N, as represented on Fig. 2.1. 2800 N 36 m / s resistive force driving force Fig. 2.1 (a) The speed of the car is constant at 36 m / s. What is the value of the driving force? driving force = … N [1] (b) Later in the journey, the car’s speed decreases uniformly from 36 m / s to zero in 18 s. (i) On the axes in Fig. 2.2, sketch the speed-time graph for the motion of the car during these 18 s. Mark 36 m / s and 18 s clearly on your graph. 0 time / s speed m / s 0 [3] Fig. 2.2 (ii) Determine the distance travelled by the car in these 18 s. distance = … m [3] [Total: 7]

4 0625/22/O/N/14 © UCLES 2014 3 (a) State two sources of energy that are renewable. 1. … 2. … [2] (b) State two sources of energy that will eventually run out or become uneconomic to extract. 1. … 2. … [2] (c) In a hydroelectric power station, water is stored high up behind a dam. (i) State the type of energy stored by the water. …[1] (ii) Explain what happens to the water in order to generate electricity. … … … [2] [Total: 7]

5 0625/22/O/N/14 © UCLES 2014 [Turn over 4 Some water forms a shallow puddle on a metal surface in a laboratory, as shown in Fig. 4.1. puddle of water metal surface Fig. 4.1 Later in the day, it is noticed that the puddle has disappeared and the metal surface is dry. (a) Which process has caused the disappearance of the puddle? Tick one box. boiling condensation evaporation freezing [1] (b) In terms of molecules, describe how this process occurs. … … …[2] (c) When this process occurs, it causes cooling. In terms of molecules, explain why this cooling occurs. … … …[2] [Total: 5]

6 0625/22/O/N/14 © UCLES 2014 5 Here are some statements about forces. Some statements are correct. Put a tick () in the box alongside each of these. Other statements are false. Put a cross () in the box alongside each of these. On Earth, an object has weight due to a force acting towards the Earth. Work is done when an object moves in the direction of the force acting on it. When a single force acts on an object, it moves at constant speed. If the only forces acting on an object are two equal and opposite forces in the same straight line, then the object is in equilibrium. An object at rest always has no forces acting on it. [5] [Total: 5]

7 0625/22/O/N/14 © UCLES 2014 [Turn over 6 (a) A laboratory liquid-in-glass thermometer has a range from –10 °C to 110 °C. Describe what you would do to check the accuracy of (i) the 0 °C mark on the thermometer, … … …[2] (ii) the 100 °C mark on the thermometer. … … …[1] (b) The temperature of some water is reduced to –10 °C. In which state is the water at this temperature? …[1] (c) The measurement of temperature can be carried out using any physical property that changes with temperature. Two examples are given below. the volume of a liquid the resistance of a wire Add two more examples. You may re-use words from the examples if you wish, but you do not have to do so. 1. the of 2. the of [2] [Total: 6]

8 0625/22/O/N/14 © UCLES 2014 7 Four school athletes are about to run a 100 m race, as shown in Fig. 7.1. 100 m winning line B A timekeeper starting pistol starter Fig. 7.1 (not to scale) The runners start at A, when the starter fires the starting pistol, and they finish at B. (a) Suggest what equipment (i) the groundsman used when he measured out the 100 m before marking the track, … (ii) the timekeeper uses to time how long the runners take to run the 100 m. … [2] (b) The timing instrument is known to work correctly. What might cause the timekeeper to introduce an inaccuracy into the timing of the race? …[1]

9 0625/22/O/N/14 © UCLES 2014 [Turn over (c) The winner takes 12.5 s to run the race. (i) Calculate the average speed of the winner. average speed = … m / s [3] (ii) Suggest one reason why the average speed of the winner is less than his top speed. …[1] (d) On another occasion, the starter and timekeeper decide to measure the speed of the sound from the gun. They use the same equipment they used to time the race. (i) Suggest how far apart they should be. … (ii) Suggest how the timekeeper would know when to start timing. … … [2] [Total: 9]

10 0625/22/O/N/14 © UCLES 2014 8 Fig. 8.1 shows a section through the swimming pool in a hotel. To make the pool more attractive at night, there are submerged lamps in the pool. Fig. 8.1 shows three rays coming from one of these lamps. 40° 50° 30° air water lamp B A Fig. 8.1 The critical angle for the water/air boundary is 48 °. (a) State what is meant by the critical angle for a ray of light. … … …[3] (b) On Fig. 8.1, use your ruler to draw approximate paths for the rays after they reach the surface at A and B. [4] [Total: 7]

11 0625/22/O/N/14 © UCLES 2014 [Turn over 9 (a) Which electrical quantity does a voltmeter measure? Tick one box. current potential difference power resistance [1] (b) The transformer in Fig. 9.1 has 600 turns on its primary coil AB, and 400 turns on its secondary coil CD. A B C D primary coil 600 turns secondary coil 400 turns iron core Fig. 9.1 (i) AB is connected to a 120 V alternating mains supply. An a.c. voltmeter is connected across CD. Calculate the reading on the voltmeter. voltmeter reading = … V [3] (ii) A large number of cells are connected in series, to make a 120 V battery. The mains supply is disconnected from AB, and the 120 V battery is connected in its place. 1. State the voltage across CD. … 2. Explain your answer. … … [2] [Total: 6]

12 0625/22/O/N/14 © UCLES 2014 10 A student is attempting to measure the resistance of a resistor R. To do this, she connects the circuit of Fig. 10.1. R E S Fig. 10.1 (a) The letter E on Fig. 10.1 represents the electromotive force (e.m.f.) of the battery. In which unit is E measured? … [1] (b) The circles on Fig. 10.1 represent a voltmeter and an ammeter. Write V and A in the appropriate circles, to show which meter is which. [1] (c) The battery cannot be changed. (i) Write down the label of the component that is used to vary the current in the circuit. … (ii) What is this component called? … [2] (d) The table below gives the readings obtained by the student for different currents. ammeter reading / A 0 0.20 0.30 0.50 0.75 1.00 voltmeter reading / V 0 1.15 1.65 2.65 4.10 5.55

13 0625/22/O/N/14 © UCLES 2014 [Turn over (i) On Fig. 10.2, draw a graph of these values. The first two points have been plotted for you. [2] 0 0 1 2 3 4 5 6 0.2 0.4 0.6 ammeter reading / A voltmeter reading / V 0.8 1.0 Fig. 10.2 (ii) Use your graph to find a value for the resistance of R. resistance = … Ω [3] [Total: 9]

14 0625/22/O/N/14 © UCLES 2014 11 The radiation detector and counter in Fig. 11.1 are being used to count particles from a radioactive source. counter radiation detector Y X Fig. 11.1 Each time the counter is used to make a measurement, it is first reset to zero and then left switched on for 3 minutes. (a) With no radioactive source anywhere near the radiation detector, after being switched on for 3 minutes the reading on the counter is 85 counts. Suggest what radiation caused this reading. …[1] (b) A radioactive source emitting β-particles is placed at X. After 3 minutes, the counter reads 592 counts. Calculate the average count rate, in counts / min, from the radioactive source. count rate = … counts / min [3] (c) The β-particle source is left at X and a block of aluminium 4 cm thick is placed at Y. (i) Suggest what the counter would read on this occasion, after 3 minutes. … (ii) Explain your answer to (c)(i). … … [3] [Total: 7]

15 0625/22/O/N/14 © UCLES 2014 12 Fig. 12.1 is a very simple representation of the structure of an atom. – nucleus – – – + + + + Fig. 12.1 The broken circle indicates the nucleus, and the particles inside this broken circle are the particles in the nucleus. Charged particles are marked + or –. Uncharged particles are shown as empty circles. (a) State the number of neutrons in this atom. … [1] (b) State (i) the nucleon number of the atom, … (ii) the proton number of the atom. … [2] (c) What name is given to the negatively-charged particles? … [1] [Total: 4]

16 0625/22/O/N/14 © UCLES 2014 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. 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. BLANK PAGE

® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International General Certificate of Secondary Education MARK SCHEME for the October/November 2014 series 0625 PHYSICS 0625/22 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 October/November 2014 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 – October/November 2014 0625 22 © Cambridge International Examinations 2014 NOTES ABOUT MARK SCHEME SYMBOLS AND OTHER MATTERS B marks B marks are independent marks, which do not depend on other marks. For a B mark to be scored, the point to which it refers must be seen specifically in the candidate’s answer. M marks 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 C marks are compensatory marks in general applicable to numerical questions. These can be scored even if the point 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 substitution or working which shows he knew the equation, then the C mark is scored. A C mark is not awarded if a candidate makes two points which contradict each other. Points which are wrong but irrelevant are ignored. A marks 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. A marks are commonly awarded for final answers to numerical questions. If a final numerical answer, eligible for A marks, is correct, with the correct unit and an acceptable number of significant figures, all the marks for that question are normally awarded. It is very occasionally possible to arrive at a correct answer by an entirely wrong approach. In these rare circumstances, do not award the A mark, but award C marks on their merits. An A mark following an M mark is a dependent mark. Brackets ( ) 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. Underlining Underlining indicates that this must be seen in the answer offered, or something very similar. OR / or This indicates alternative answers, any one of which is satisfactory for scoring the marks. e.e.o.o. This means "each error or omission". o.w.t.t.e. This means “or words to that effect”. Ignore This indicates that something which is not correct or irrelevant is to be disregarded and does not cause a right plus wrong penalty. Spelling Be generous about spelling and use of English. If an answer can be understood to mean what we want, give credit. However, do not allow ambiguities, e.g. spelling which suggests confusion between reflection / refraction / diffraction or thermistor / transistor / transformer. Not / NOT This 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 3 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0625 22 © Cambridge International Examinations 2014 ecf meaning "error carried forward" is mainly applicable to numerical questions, but may in particular circumstances be applied in non-numerical questions. This indicates that if a candidate has made an earlier mistake and has carried an incorrect value forward to subsequent stages of working, marks indicated by ecf may be awarded, provided the subsequent working is correct, bearing in mind the earlier mistake. This prevents a candidate from being penalised more than once for a particular mistake, but only applies to marks annotated ecf. Sig. figs. Answers are normally acceptable to any number of significant figures ≥ 2. Any exceptions to this general rule will be specified in the mark scheme. Arithmetic errors Deduct one mark if the only error in arriving at a final answer is clearly an arithmetic one. Regard a power-of-ten error as an arithmetic error. Transcription errors Deduct one mark if the only error in arriving at a final answer is because previously calculated data has clearly been misread but used correctly. Fractions Allow fractions only where specified in the mark scheme.

Page 4 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0625 22 © Cambridge International Examinations 2014 1 (a) last 2 boxes ticked B2 (b) (i) 267 (g) B1 (ii) LHS goes down OR RHS goes up B1 (iii) density = mass / volume, in any form e.g. words, symbols, numbers C1 267 / 30 C1 8.9 A1 g / cm3 B1 [Total: 8] 2 (a) 2800 (N) B1 (b) (i) straight line B1 line slopes down M1 clearly indicated on axes 36 (m / s) and 18 (s) A1 (ii) area under graph OR distance = (average) speed × time, in any form C1 ½ × 36 × 18 C1 324 (m) A1 [Total: 7] 3 (a) any two from: waves wind hydro(electric) tidal geothermal solar biofuel / biomass wood B2 (b) any two from: coal oil OR any stated refined fuel (natural) gas nuclear B2 (c) (i) gravitational potential (energy) B1 (ii) water falls / drops OR GPE transferred to KE B1 spins / turns / moves turbine /generator B1 [Total: 7]

Page 5 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0625 22 © Cambridge International Examinations 2014 4 (a) evaporation B1 (b) molecules escape (from the surface) M1 if they gain / have enough energy owtte A1 (c) more energetic / faster molecules escape B1 lower (average) energy (results in lower temperature) OR energy flows from metal into water causing metal to cool B1 [Total: 6] 5
B1
B1 x B1
B1 x B1 [Total: 5] 6 (a) (i) ice M1 pure OR melting A1 (ii) boiling water OR steam M1 (b) solid B1 (c) any two from: resistance of thermistor pressure / volume / expansion of a gas volume / length / expansion of a solid / metal e.m.f. of a thermocouple colour of a surface / liquid crystal melting point of waxes density of liquid (in Galileo thermometer) B2 [Total: 6] 7 (a) (i) tape measure OR laser measure OR trundle wheel B1 (ii) stopwatch / stopclock B1 (b) reaction time owtte OR delay in hearing sound B1 (c) (i) (speed =) distance ÷ time C1 100 ÷ 12.5 C1 8.0 (m / s) A1

Page 6 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0625 22 © Cambridge International Examinations 2014 (ii) acceleration (at the start) or similar idea OR indication of slowing down at the end (due to tiredness) B1 (d) (i) 200 m – 500 m B1 (ii) means of signalling when gun fired such as dropped arm or smoke seen B1 [Total: 9] 8 (a) (maximum) angle of incidence B1 for a ray to be just refracted / emerge OR resulting in an angle of refraction of 90o B1 beyond this angle the ray is totally internally reflected OR ray travelling from (optically) dense medium to less dense medium B1 (b) ray at A: one emergent ray and one reflected ray B1 refracted away from normal B1 ray at B: one reflected ray only B1 angle of reflection is 50° by eye B1 [Total: 7] 9 (a) potential difference B1 (b) (i) V1 / V2 = N1 / N2 in any form C1 correct substitution C1 80 (V) A1 (ii) 1. zero OR 0 (V) M1 2. idea of requirement of varying field / flux linkage A1 [Total: 6] 10 (a) volts OR V B1 (b) A and V in correct circles B1 (c) S OR symbol for variable resistor M1 variable resistor OR rheostat A1 (d) (i) points correctly plotted to ½ small square B1 good best-fit straight line through all points B1

Page 7 Mark Scheme Syllabus Paper Cambridge IGCSE – October/November 2014 0625 22 © Cambridge International Examinations 2014 (ii) use of any V from table / graph OR large triangle drawn on graph C1 calculation using V / I OR gradient calculation C1 5.2 – 5.8 (Ω) A1 [Total: 9] 11 (a) background OR reasonable source of background B1 (b) 592 – 85 OR 507 seen OR used B1 507 / 3 accept 592 / 3 (i.e. background not deducted) C1 169 counts / min accept 197.3 counts / min (i.e. background not deducted) A1 Note: a candidate who does not deduct background but whose answer is otherwise correct will gain two marks. (c) (i) 85 OR “approx. 85” B1 (ii) aluminium absorbs (β) radiation OR stops (β) radiation B1 only background count left OR reading goes back to value in (a) B1 [Total: 7] 12 (a) 5 B1 (b) (i) 9 B1 (ii) 4 B1 (c) electrons B1 [Total: 4]