Cambridge IGCSE Physics 0625 — 2025 Oct/Nov Paper 6 · Variant 3

1 A student determines the volume of a block of modelling clay by two methods. Method 1 He measures the block of modelling clay shown full size in Fig. 1.1. l w h Fig. 1.1 (a) (i) Measure the length l, width w and height h of the block of modelling clay on Fig. 1.1. Record your values in centimetres to the nearest millimetre. length l = .......................................................... cm width w = .......................................................... cm height h = .......................................................... cm [2] (ii) Calculate a value VA for the volume of the block. Use your measurements from (a)(i) and the equation: VA = l × w × h. VA = ................................................... cm3 [1] (b) Suggest why VA is only an approximate value for the volume of the block. Describe how the accuracy of VA can be improved. suggestion ................................................................................................................................ ................................................................................................................................................... improvement ............................................................................................................................. ................................................................................................................................................... [2] (c) Another student measures the dimensions of a block of clay which is much smaller than the block in (a). Suggest why these measurements may not be as accurate as yours, even if they are done carefully. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [1] Method 2 (d) (i) The student pours water into a measuring cylinder. Record the volume V1 of the water in the measuring cylinder shown in Fig. 1.2. V1 = ................................................... cm3 [1] 160 measuring cylinder 150 water Fig. 1.2 (ii) Describe briefly how a measuring cylinder is read to obtain an accurate value for the volume of water. ........................................................................................................................................... ..................................................................................................................................... [1] (e) The student lowers the modelling clay into the water using a loop of thread, as shown in Fig. 1.3. 210 thread 200 block of clay Fig. 1.3 Record the new reading V2 shown on the measuring cylinder scale in Fig.1.3. V2 = ......................................................... cm3 Calculate another value VB for the volume of the block. Use your measurements from (d)(i) and (e) and the equation: VB = (V2 – V1). VB = ......................................................... cm3 [1] (f) Suggest one possible source of inaccuracy in Method 2 and suggest one improvement to reduce its effect. source of inaccuracy ................................................................................................................. ................................................................................................................................................... improvement ............................................................................................................................. ................................................................................................................................................... [2] [Total: 11]

Mark scheme: Question Answer Marks 1(a)(i) l = 6.9 (cm) w = 2.5 (cm) h = 3.0 (cm) 2 all to nearest mm 1(a)(ii) VA = 52 (cm3) 1 1(b) irregular dimensions / owtte 2 repeat in several places (for each dimension) and take averages 1(c) effect of uncertainties increased/ 1 larger % uncertainty/owtte 1(d)(i) V1 = 152 (cm3) 1 1(d)(ii) line of sight perpendicular / owtte 1 1(e) V2 present and VB = V2 -V1 1(f) suitable source of inaccuracy 2 e.g. graduations on measuring cylinder too large / thread affects volume / cylinder is wide / clay may absorb water matching improvement e.g. use smaller measuring cylinder / more precise scale / thinner thread / no thread and place carefully / measure volume of thread / narrower cylinder / cover clay with paint or cling film

More questions on Physical quantities and measurement techniques

2 A student investigates the resistances of identical wires connected in parallel. She uses the circuit shown in Fig. 2.1. RP X Y A A wire A B wire B C wire C crocodile clips Fig. 2.1 (a) On Fig. 2.1, draw a voltmeter connected so that it will measure the potential difference (p.d.) across terminals X and Y. [1] Circuit A (b) The student connects crocodile clip A to a length l = 80.0 cm of resistance wire A. (i) On Fig. 2.2, draw an arrow ( ) to indicate precisely between which two points she should measure l = 80.0 cm for wire A. [1] wire A A Fig. 2.2 (ii) The student measures the potential difference V across terminals X and Y and measures the current I in the circuit. The readings on the meters are shown in Fig. 2.3 and Fig. 2.4. 2 3 0.4 0.6 1 4 0.2 0.8 0 5 0 1.0 V A Fig. 2.3 Fig. 2.4 Read, and record in the first line of Table 2.1, the values of V and I shown on the meters in Fig. 2.3 and Fig. 2.4. Table 2.1 circuit V / V I / A R / Ω A B 2.2 0.59 C 1.8 0.72 [2] (c) Circuit B The student connects crocodile clip B to a length l = 80.0 cm of resistance wire B so that wires A and B are connected in parallel. Circuit C The student connects crocodile clip C to a length l = 80.0 cm of resistance wire C so that wires A, B and C are connected in parallel. In each circuit, she measures the potential difference V across terminals X and Y and measures the current I in the circuit. Her readings are shown in Table 2.1. Calculate, and record in Table 2.1, the resistance R of each wire combination. Use the equation: V R = . I [2] (d) (i) Record a resistance RA. RA is the value of R from Circuit A. RA = ............................................................ Ω Calculate a resistance RB. Use the value of R from Circuit B and the equation: RB = R × 2 RB = ............................................................ Ω Calculate a resistance RC. Use the value of R from Circuit C and the equation: RC = R × 3 RC = ............................................................ Ω [1] (ii) A student suggests that the values of RA, RB and RC should be equal. State whether your results support this suggestion. Use values from your results to justify your answer. statement ........................................................................................................................... justification ......................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... [2] (e) Briefly explain why resistor RP , shown in Fig. 2.1, must remain in place throughout the experiment. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [1] (f) One possible problem with this type of experiment is heating of the resistance wires. Suggest what to do to reduce this. ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [1] [Total: 11]

Mark scheme: 2(a) correct voltmeter symbol connected in parallel 1 2(b)(i) arrow between left-hand end of wire and left-hand side of crocodile clip 1 2(b)(ii) V = 2.9 (V) 2 I = 0.36 (A) 2(c) R = 8.06 and 3.73 and 2.50 () OR 2 8.1 and 3.7 and 2.5 () consistent 2 or consistent 3 significant figures 2(d)(i) RA = 8.06, RB = 7.46 and RC = 7.50 () OR 1 RA = 8.1, RB = 7.4 OR 7.5 and RC = 7.5 () 2(d)(ii) statement matching results 2 within limits of experimental accuracy / within 10% / owtte 2(e) limits current / current could exceed fsd value of ammeter 1 2(f) suitable action: 1 reduce voltage of power supply / connect to longer wire / use RP of greater value / switch off circuit between taking readings

More questions on Electrical quantities

3 A student investigates the image produced by a converging lens. He uses the equipment shown in Fig. 3.1. illuminated screen triangular object u lens hO bench Fig. 3.1 (not to scale) (a) The student sets the distance u between the illuminated triangular object and the lens to 20.0 cm. He moves the screen until a sharp image of the illuminated triangular object is seen on the screen. Briefly describe one technique to obtain an image on the screen which is as sharp as possible in this experiment. ................................................................................................................................................... ............................................................................................................................................. [1] (b) (i) The screen is shown full size in Fig. 3.2. Measure, and record in the first line of Table 3.1, the height hI of the image on the screen, as shown in Fig. 3.2. hI Fig. 3.2 Table 3.1 1 u / cm hI / cm D / cm 20.0 25.0 2.8 0.36 30.0 2.0 0.50 35.0 1.6 0.63 40.0 1.2 0.83 [1] (ii) For distance u = 20.0 cm, calculate, and record in Table 3.1, a value D. Use your value of hI from Table 3.1 and the equation: 1 D = . hI [1] (c) The student repeats the procedure for u = 25.0 cm, u = 30.0 cm, u = 35.0 cm and u = 40.0 cm. His results are shown in Table 3.1. 1 Plot a graph of u / cm (y‑axis) against D / (x‑axis). Start the axes at the origin (0,0). cm Draw a best‑fit straight line. [4] (d) (i) From your graph, determine u0, the value of u when D is zero. u0 = .................................................... cm [1] (ii) Determine the gradient G of the graph. Show clearly on the graph how you obtained the necessary information. G = .......................................................... [1] (e) The illuminated object is shown full size in Fig. 3.3. Measure and record the height hO of the illuminated triangular object shown in Fig. 3.3. hO = .......................................................... cm hO Fig. 3.3 Calculate the focal length f of the lens. Use your value of hO, your value of G from (d)(ii) and the equation: G f = × k, where k = 1.0 cm2. hO f = .......................................................... cm [1] (f) Describe one difficulty that can be experienced when measuring the height of the image in this experiment. Suggest an improvement to overcome this difficulty. difficulty ..................................................................................................................................... ................................................................................................................................................... improvement ............................................................................................................................. ................................................................................................................................................... [1] [Total: 11]

Mark scheme: 3(a) move screen backwards and forwards / move screen slowly 1 3(b)(i) hI = 6.0 (cm) 1 3(b)(ii) D = 0.17 (cm-1) 1 3(c) graph: 4 • axes labelled with quantity and unit • appropriate scales (occupying at least ½ grid) • plots all correct to ½ small square, precise plots • well judged line and thin line 3(d)(i) intercept read correctly from graph 1 3(d)(ii) G recorded and triangle method shown on graph 1 3(e) hO present and 1 f in range 13.5 to 16.5 (cm) 3(f) any appropriate difficulty: 1 e.g. hand/ruler in way of image / person creating a shadow and matching improvement: e.g. use translucent screen and view from behind / fix ruler or grid to screen / mark image on screen before measuring / take a photo with ruler in view

More questions on Light

4 A student investigates the evaporation of water in an open dish. Plan an experiment which will enable the student to compare the effect on evaporation of using different diameters of dish. The mass me of water evaporated can be determined by using the equation: me = mb – ma where mb = the mass of water in the dish before experiment and ma = the mass of water in the dish after experiment. The apparatus available includes: • a range of shallow dishes with different diameters • an adjustable laboratory lamp to heat the water • a variable power supply for the lamp • a stop‑watch • a supply of cold water. You do not need to write about any safety precautions. In your plan: • list any additional apparatus needed • explain briefly how to do the experiment, including what measurements need to be taken • state the key variables to keep constant • draw a table, or tables, with column headings, to show how to display the readings (you are not required to enter any readings in the table) • explain how to use the readings to reach a conclusion. You may draw a diagram or add to Fig. 4.1 if it helps to explain your plan. lamp water dish bench Fig. 4.1 .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [7]

Mark scheme: 4 MP1 apparatus: 7 ruler and balance / measuring cylinder MP2 method: measure mass / volume of water switch on lamp measure new mass / volume of water MP3 repeat for dish with new diameter MP4 control variable (one from): initial mass / volume of water, time lamp turned on, height / angle/distance of lamp, power of lamp, initial temperature of water MP5 table: columns for diameter and final mass / volume of water with units MP6 analysis: compare readings in a table to see if a change in diameter produces a change in mass / volume of water evaporated / plot line graph (with axes specified) MP7 additional point (one from): at least 5 sets of data taken, repeat each measurement and take average, 2nd control variable stated,

More questions on Kinetic particle model of matter