Cambridge IGCSE Physics 0625 — 2018 Oct/Nov Paper 5 · Variant 1

1 In this experiment, you will determine the spring constant k of a spring by two methods. Some of the apparatus has been set up for you. Carry out the following instructions, referring to Fig. 1.1 and Fig. 1.2. Method 1 (a) Measure the unstretched length l0 of the spring, in mm. l0 = ....................................................mm [1] (b) Hang the 300 g mass on the spring, as shown in Fig. 1.1. clamp holding spring spring clamp holding cork mass pin in cork bench Fig. 1.1 (i) Measure the new length l of the spring. l = ....................................................mm [1] (ii) Use the equation e = (l – l0) to calculate the extension e of the spring. e = ....................................................mm [1] F = , where F = 3.0 N. (iii) Calculate a value for the spring constant k using the equation k e k = ............................................... N / mm [1] Method 2 (c) Adjust the position of the lower clamp so that the pin is level with the bottom of the mass when the mass is not moving. Pull the mass down about 1.5 cm and release it so that it oscillates up and down. Fig. 1.2 shows one complete oscillation. clamp holding spring clamp holding cork one complete oscillation bench Fig. 1.2 (i) Measure the time t taken for 10 complete oscillations. Start the stopwatch as the bottom of the mass passes the pin. t = ........................................................s [1] (ii) 1. Calculate the time T taken for one complete oscillation. T = .............................................................s 2. Calculate T 2. T 2 = ............................................................... [1] 0. 040 m = (iii) Calculate the spring constant k using the equation k 2 , where m = 0.300 kg. T k = ............................................... N / mm [1] (d) State and explain briefly whether your two values for k are the same within the limits of experimental accuracy. statement .................................................................................................................................. explanation ............................................................................................................................... ................................................................................................................................................... [2] (e) A student states that repeating Method 1 with different masses would improve the reliability of the value obtained for k. Suggest additional values for the mass m that you would use when repeating the experiment to improve the reliability. ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[2] [Total: 11]

Mark scheme: 1(a) l0 sensible value, in mm 1 1(b)(i) Sensible l greater than l0 1 1(b)(ii) Correct calculation of e 1 1(b)(iii) k calculated correctly 1 1(c)(i) t sensible 1 1(c)(ii) T = t / 10 and T2 present with unit s2 1 1(c)(iii) Correct k within 20% of previous value 1 1(d) Statement matches results 1 Idea of within (or beyond) limits of experimental accuracy explained, e.g. close enough, very close, too far apart 1 1(e) At least 3 additional values given 1 Values between 50 g and 600 g 1

More questions on Physical quantities and measurement techniques

2 In this experiment, you will determine the resistance of a piece of wire. power supply A l P sliding wire contact C V Fig. 2.1 (a) (i) Carry out the following instructions, referring to Fig. 2.1. • Switch on. • Measure the current I in the circuit. I = ...........................................................[1] (ii) Place the sliding contact C at a distance l = 20.0 cm from P. • Measure, and record in Table 2.1, the reading on the voltmeter. • Repeat the procedure using l values of 40.0 cm, 60.0 cm, 80.0 cm and 100.0 cm. • Switch off. Table 2.1 l / cm V / V 20.0 40.0 60.0 80.0 100.0 [2] (b) Plot a graph of V / V (y-axis) against l / cm (x-axis). Start both axes at the origin (0,0). [4] (c) (i) Determine the gradient G of the graph. Show clearly on the graph how you obtained the necessary information. G = ...........................................................[2] G k (ii) Calculate the resistance R of each centimetre of the wire. Use the equation R = , I where k = 1.0 V / cm and I is the current recorded in (a)(i). Include the unit. R = ...........................................................[2]

Mark scheme: 2(a)(i) 1 2(a)(ii) V values to at least 1 dp and < 4 V 1 V values increasing 1 2(b) Graph: Axes correctly labelled and right way round 1 Suitable scales 1 All plots correct to ½ small square 1 Good line judgement, single, thin, continuous line 1 2(c)(i) Triangle method seen on graph 1 At least half of candidate’s line used and G present 1 2(c)(ii) R correct to 2 or 3 significant figures 1 Unit Ω / cm OR Ω 1

More questions on Electrical quantities

3 In this experiment, you will determine the refractive index n of the material of a transparent block. E hole N F A B D C G L eye Fig. 3.1 (a) Carry out the following instructions, using the separate ray-trace sheet provided. Refer to Fig. 3.1 for guidance. • Place the transparent block, largest face down, on the ray-trace sheet supplied. The block should be approximately in the middle of the paper. • Draw and label the outline of the block ABCD. • Remove the block and draw the normal NL at the centre of side AB. Continue the normal so that it passes through side CD of the block. • Label the point F where NL crosses AB. • Label the point G where NL crosses CD. [2] (b) • Draw the line EF at an angle i = 30° to the normal as shown in Fig. 3.1. • Place the paper on the pin board. • Place two pins P1 and P2 on line EF at a suitable distance apart for this experiment. • Replace the block and look from the position of the eye shown in Fig. 3.1, to observe the images of P1 and P2 through side CD of the block. Adjust your line of sight until the images of P1 and P2 appear one behind the other. • Place two pins P3 and P4 between your eye and the block so that P3, P4, and the images of P1 and P2 seen through the block, appear one behind the other. • Label the positions of P1, P2, P3 and P4. • Remove the block and the pins. • Draw a line joining the positions of P3 and P4. Continue the line until it meets the normal NL. • Label the point H where the line meets side CD. Draw the line FH. [1] (c) (i) Measure and record the length a of the line GH. a = ...........................................................[1] (ii) Measure and record the length b of the line FH. b = ...........................................................[1] 0 .50 b = . (iii) Calculate the refractive index n using the equation n a n = ...........................................................[2] (d) Repeat the procedure in (b) using an angle i = 45º. (i) Repeat the measurements in (c)(i) and (c)(ii) for i = 45º. a = ............................................................... b = ............................................................... [1] 0 .71 b = . (ii) Calculate the refractive index n using the equation n a n = ...........................................................[1] (e) A student carries out this experiment with care and expects the two values of refractive index n obtained in this experiment to be equal. State two difficulties with this type of experiment that could explain any difference in the two values of n. 1. ............................................................................................................................................... ................................................................................................................................................... 2. ............................................................................................................................................... ................................................................................................................................................... [2] [Total: 11] Tie your ray-trace sheet into this Question Booklet between pages 10 and 11.

Mark scheme: 3(a) Ray-trace: Normal through block 1 Normal at centre of AB 1 3(b) Ray-trace: P1 and P2 at minimum distance apart of 5.0 cm 1 3(c)(i) a correct to ± 1 mm 1 3(c)(ii) b correct to ± 1 mm and both with correct unit 1 3(c)(iii) n correct, 2 or 3 significant figures with no unit 1 n = 1.35 to 1.64 1 3(d)(i) Second set of lines seen on trace in approximately correct positions and a and b recorded 1 3(d)(ii) n within 10% of value in (b) 1 3(e) Any two from: Lining up the pins exactly / seeing pins clearly Drawing accurate, thin lines Getting pins vertical Replacing block accurately on outline / outline larger than block / owtte 2

More questions on Light

4 A student is investigating the relationship between the power produced by an electrical heater and the time taken to heat a beaker of water. The power of the heater is given by the equation P = VI, where V is the potential difference (p.d.) across the heater and I is the current in the heater. Plan an experiment to investigate the relationship between the power produced by an electrical heater and the time taken to heat a beaker of water. You are not required to carry out this investigation. The following apparatus is available: ammeter voltmeter 0–12 V variable power supply 250 cm3 beaker heater thermometer stopwatch The student can also use other apparatus and materials that are usually available in a school laboratory. You should: • complete the diagram in Fig. 4.1 to show the circuit that you would use • explain briefly how you would carry out the investigation • state the key variables that you would control • draw a table with column headings, to show how you would display your readings (you are not required to enter any readings in the table) • explain how you would use your results to reach a conclusion. beaker heater water Fig. 4.1 .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[7] [Total: 7]

Mark scheme: 4 MP1 Workable, correct circuit diagram with power source and correct symbols for ammeter and voltmeter. 1 Method to include: MP2 Measuring V and I 1 MP3 Repeating with at least two other values of V or power, and / or I 1 MP4 Measuring time to raise water temperature 1 MP5 Any ONE from: Same starting temperature Same finishing temperature Same temperature difference Same room temperature Same volume / mass / amount of water 1 MP6 Table with clear columns for time, V and I, with appropriate units and P (or VI) 1 MP7 Conclusion: Plot a graph of power against time. 1

More questions on Energy, work and power