Cambridge IGCSE Physics 0625 — 2011 Oct/Nov Paper 2 · Variant 2

This document consists of 16 printed pages. DC (NF/SW) 34010/4 © UCLES 2011 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education * 6 5 8 8 4 8 2 6 8 0 * PHYSICS 0625/22 Paper 2 Core October/November 2011 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 a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. 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. www.XtremePapers.com

2 0625/22/O/N/11 © UCLES 2011 1 (a) An empty glass beaker has a mass of 210 g. When 200 cm3 of olive oil is poured into the beaker, the total mass is 394 g. Calculate the density of the olive oil. density = … [4] (b) When the beaker and olive oil are heated, the olive oil expands. What happens to the density of the olive oil? … [1] [Total: 5] 2 (a) Describe what is meant by an echo. … … … [2] (b) Fig. 2.1 shows the mouth of a river, viewed from above. A and B are on opposite banks, and are 800 m apart. A B 800 m Fig. 2.1

3 0625/22/O/N/11 © UCLES 2011 [Turn over Echo depth measurements use the time taken for sound to go from the surface to the river bed and back again. Such measurements give the following values for the depth of the water at different distances from A, along the line AB. distance from A / m 0 100 200 300 400 500 600 700 800 depth of water / m 0 1.8 5.1 12.9 18.9 22.2 16.5 6.3 0 (i) The speed of sound in water is 1500 m / s. Calculate how long a sound wave takes to travel from the surface to the bottom of the river at a point 300 m from A. time = … s [3] (ii) A ship has 3 m of itself below the surface of the water. From the figures in the table, estimate how close to A it can sail without hitting the bottom of the river. distance from A = … m [1] [Total: 6]

4 0625/22/O/N/11 © UCLES 2011 3 (a) State what is meant by the moment of a force. … … [1] (b) A warehouse worker is about to close a large door, as shown in Fig. 3.1. A B Fig. 3.1 (i) State, with a reason, which of the two positions, A or B, will enable him to close the door with least force. … … … [1] (ii) On another occasion, with the door in the position shown in Fig. 3.1, two workers each push on the door with the same force at the same time. One worker pushes at A, from the side seen in Fig. 3.1. The other worker pushes at B, from the other side of the door. Which way does the door move, if at all? Tick one box. the door closes the door opens the door remains as it is [1] [Total: 3]

5 0625/22/O/N/11 © UCLES 2011 [Turn over 4 (a) State what is meant by the term melting point. … … [2] (b) Some ice has all reached its melting point, and it begins to melt. What happens to the temperature of the ice as it melts? … [1] (c) A certain substance has a melting point of –10 °C (minus 10 °C). A small amount of this substance is cooled from 50 °C to –18 °C in a very cold freezer unit. On Fig. 4.1, sketch a possible graph that shows how the temperature of the substance varies with time during the cooling process. –60 0 –40 –20 20 40 60 temperature / °C time Fig. 4.1 [4] [Total: 7]

6 0625/22/O/N/11 © UCLES 2011 5 The circuit in Fig. 5.1 is connected, and the ammeter reading is noted as the water is heated. A X insulated connecting wires heat Fig. 5.1 It is found that the ammeter reading increases as the temperature rises. (a) (i) State what happens to the resistance of component X as the temperature rises. … [1] (ii) Suggest what component X might be. … [1] (b) This circuit is to be used as a thermometer. (i) What must be done to calibrate it 1. at 0°C, … … … [2] 2. at 100 °C? … … … [3]

7 0625/22/O/N/11 © UCLES 2011 [Turn over (ii) The resistance of X does not vary linearly with temperature between 0 °C and 100 °C. How will this affect the use of this circuit as a thermometer? … … … [2] [Total: 9]

8 0625/22/O/N/11 © UCLES 2011 6 (a) In a laboratory optics experiment, a student stands a cylindrical converging lens on a large piece of paper and shines two parallel rays of light into it. This is shown in Fig. 6.1. P P P P Q Q parallel rays of light converging lens Q Q Fig. 6.1 The student traces one of the rays using four pins, labelled P in Fig. 6.1. He traces the other ray using four more pins, labelled Q. (i) Using a ruler, draw 1. the paths of the two rays in the air to the right of the lens, 2. the paths of the two rays as they pass through the lens. (ii) On Fig. 6.1, use the letter F to label the principal focus of the lens. [3]

9 0625/22/O/N/11 © UCLES 2011 [Turn over (b) Fig. 6.2 shows part of the path of a ray of light through a glass block. The critical angle for the glass/air boundary is 42°. A B air ray of light glass block C Fig. 6.2 (i) State the name that describes what is happening to the ray 1. at A, … 2. at B. … [3] (ii) On Fig. 6.2, draw the path of the ray after it has reached C. [2] [Total: 8]

10 0625/22/O/N/11 © UCLES 2011 7 Plane waves travel on the surface of some water in a tank. Fig. 7.1 shows the appearance, from above, of the waves before and after the boundary between two different depths of water in the tank. waves move this way boundary L R Fig. 7.1 (a) State what happens to the wavelength as the waves cross the boundary. … [1] (b) Water waves travel more slowly when the water is shallower, but the frequency does not change. (i) State, giving your reasons, which side of the boundary, L or R, has the deeper water. … … … … [3] (ii) Some more water is poured into the tank, and waves of the same frequency as before are generated in the tank. What difference, if any, will this make to the appearance of the waves 1. to the left of the boundary, … 2. to the right of the boundary? … [2] [Total: 6]

11 0625/22/O/N/11 © UCLES 2011 [Turn over 8 (a) Two charged metal spheres are placed next to each other. + indicates that the sphere is positively charged. – indicates that the sphere is negatively charged. In the box alongside each pair of spheres, write “attract” or “repel” or “no effect” to describe the effect the spheres have on each other. (i) + – (ii) + + (iii) – – [3] (b) Water is flowing in a very narrow stream from a water tap (faucet). A negatively-charged plastic strip is held close to the stream of water, as shown in Fig. 8.1. tap (faucet) negatively-charged plastic strip X water Fig. 8.1 The stream of water moves towards the plastic strip. In terms of the water at the point labelled X, suggest why this happens. … … … … [3] [Total: 6]

12 0625/22/O/N/11 © UCLES 2011 9 (a) Two coils are wound on an iron rod, as shown in Fig. 9.1. One coil is connected to a cell and a switch. The other is connected to a sensitive centre-zero millivoltmeter. sensitive centre-zero millivoltmeter iron rod Fig. 9.1 (i) The open switch is now closed. State what happens to 1. the iron rod, … [1] 2. a small steel pin held close to one end of the iron rod, … [1] 3. the needle of the millivoltmeter. … … [2] (ii) The switch is opened again. State what happens to the needle of the millivoltmeter. … … [1]

13 0625/22/O/N/11 © UCLES 2011 [Turn over (b) You are given an iron bar, a length of insulated wire, a battery and a variable resistor. You are to make an electromagnet whose strength can be varied. (i) In the space below, draw a diagram of the electromagnet that includes the circuit. [2] (ii) What is the setting of the variable resistor that gives the strongest magnetism of the electromagnet? … [1] [Total: 8]

14 0625/22/O/N/11 © UCLES 2011 10 The circuit in Fig. 10.1 is connected. The potential difference across resistor R is measured as 8.0 V. A A A ammeter 2 ammeter 1 ammeter 3 current reading = 2.0 A 4.0 Ω R potential difference = 8.0 V Fig. 10.1 (a) (i) What instrument is used to measure the potential difference across R? … [1] (ii) On Fig. 10.1, draw this instrument in position in the circuit, using the correct circuit symbol. [2] (b) The reading on ammeter 1 is 2.0 A. State (i) the reading on ammeter 2, … (ii) the reading on ammeter 3. … [2] (c) Using the values on Fig. 10.1, calculate (i) the resistance of R, resistance = … Ω [3] (ii) the total resistance of the circuit. total resistance = … Ω [1] (d) State the value of the potential difference across the 4.0 Ω resistor. potential difference = … [1] [Total: 10]

15 0625/22/O/N/11 © UCLES 2011 [Turn over 11 The count rate from a sample of radioactive material is measured every 20 minutes for 2 hours. The results, suitably corrected for background radiation, are shown in the table. time / s 0 20 40 60 80 100 120 count rate counts / s 280 210 164 122 88 72 54 (a) Suggest one possible source for the background radiation. … [1] (b) Name the two types of particle that the radioactive material might be emitting. 1. … 2. … [2] (c) From the table, without attempting a graph, estimate the half-life of the radioactive material. half-life = … s [1] (d) A similar experiment is carried out, using a larger quantity of the same radioactive material. State what effect, if any, this has on (i) the readings in the table, … [1] (ii) the half-life of the material. … [1] (e) State one precaution that should be taken for safe handling of the radioactive material. … … [1] [Total: 7] Question 12 is on the next page.

16 0625/22/O/N/11 © UCLES 2011 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. University of 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. 12 Fig. 12.1 represents the radioactive decay of a 238 92U nucleus. U 238 92 Th A Z He 4 2 Fig. 12.1 (a) In the space below, write the nuclear equation for this decay, including the numerical values of A and Z. [3] (b) What does the letter A stand for? … [1] (c) What does the letter Z stand for? … [1] [Total: 5]

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2011 question paper for the guidance of teachers 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 must be read in conjunction with the question papers and the report on the examination. • Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the October/November 2011 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 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. e.g. 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. 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". 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 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. Spelling Be generous about spelling and use of English. If an answer can be understood to mean what we want, give credit. Significant Answers are acceptable to any number of significant figures ≥ 2, except if figures specified otherwise, or if only 1 sig. fig. is appropriate. Units Incorrect units are not penalised, except where specified. More commonly, marks are allocated for specific units. Fractions These are only acceptable where specified. Extras Ignore extras in answers if they are irrelevant; if they contradict an otherwise correct response or are forbidden by mark scheme, use right + wrong = 0 Ignore Indicates that something which is not correct is disregarded and does not cause a right plus wrong penalty.

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 Not/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: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 1 (a) D = M/V in any form, letters, words, numbers C1 394 – 210 OR 184 C1 0.92 A1 g/cm3 B1 (accept correct conversion to kg/m3, with unit) (b) decreases B1 [5] 2 (a) sound/waves hitting obstacle C1 reflected/bounced back (from obstacle) A1 (b) (i) speed = distance/time in any form C1 12.9/1500 C1 0.0086 OR 8.6 × 10–3 (s) A1 (ii) 130 – 150 (m) B1 [6] 3 (a) turning effect OR force x distance (from fulcrum) B1 (b) (i) A and idea of bigger distance from hinge/pivot B1 (ii) closes B1 [3] 4 (a) temperature at which B1 change between solid and liquid (or v.v.) B1 (b) stays constant (if (b) left blank, can score from (a), if stated there) B1 (c) one section horizontal M1 at –10°C A1 curve, decreasing gradient, down to L end of horiz section from 50 at t = 0 A1 curve from R end of horiz section to –18, but no lower A1 [7] 5 (a) (i) decreases B1 (ii) thermistor B1 (b) (i) 1. put X in ice M1 pure OR melting A1 2. put X in steam/boiling water M1 pure OR standard pressure A1 record ammeter reading mentioned somewhere in (b)(i) B1 (ii) idea of not very accurate/ not linear M1 unless more calibration points (between 0°C and 100°C)/other logic A1 [9]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 6 (a) (i) 1. points P & P joined and continued back to lens surface points Q & Q joined and continued back to lens surface 2. single straight line across lens for each ray, joining incident and emerging rays B1 (ii) F clearly shown at junction of the 2 refracted rays B1 (b) (i) 1. refraction B1 2. reflection M1 total OR internal A1 (ii) refracted away from normal M1 same angle as ray striking 1st surface of block (by eye) A1 [8] 7 (a) increases B1 (b) (i) R side M1 link shown between speed & distance between waves/wavelength (accept v = fλ) A1 R side has bigger distance, so faster, so deeper (all 3 steps) A1 (accept reverse logic for L side) (ii) 1. waves further apart B1 2. waves further apart B1 [6] 8 (a) (i) attract B1 (ii) repel B1 (iii) repel B1 (b) water charged B1 opposite charge OR positive charge OR by induction B1 charge on water attracted by charge on rod B1 [6] 9 (a) (i) 1. magnetised B1 2. attracted OR magnetised B1 3. deflects M1 momentary OR then goes back to zero A1 (ii) deflects other way B1 (b) (i) electromagnet shown as coil wrapped around iron bar (interpret generously, but B0 if wire clearly connected to iron bar) B1 series circuit containing electromagnet, battery/cell, and variable resistance (condone inaccuracy of symbols, if clear) B1 both B1

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 (ii) zero/minimum/resistance B1 [8] 10 (a) (i) voltmeter NOT voltameter B1 (ii) voltmeter connected in parallel across R B1 symbol correct B1 (b) (i) 2 (A) B1 (ii) 2 (A) B1 (c) (i) R = V/I in any form C1 8/2 C1 4 (Ω) A1 (ii) candidate’s (c)(i) + 4 correctly evaluated B1 (d) 8 (V) B1 [10] 11 (a) contaminated surfaces (any sort) other radioactive material nearby (radiation from) rocks/soil cosmic rays/radiation from space radon gas from ground (b) alpha OR α B1 beta OR β B1 (–1 if gamma mentioned) (c) any value within range 45–55 B1 (d) (i) (all) larger B1 (ii) same B1 (e) any sensible precaution B1 [7] 12 (a) correct form of equation i.e. 238 92 U → A Z Th + 4 2 He B1 A clearly 234 B1 Z clearly 90 B1 (b) mass number OR nucleon number OR no. of nucleons OR no. of protons + neutrons B1 any 1 B1

Page 7 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0625 22 © University of Cambridge International Examinations 2011 (c) atomic number OR proton number OR no. of protons/positive charges IGNORE no. of electrons B1 [5]