Cambridge IGCSE Physics 0625 — 2017 May/June Paper 5 · Variant 2

1 In this experiment, you will investigate the resistance of two resistance wires. The circuit has been set up for you. Carry out the following instructions, referring to Fig. 1.1. power supply A A B C D S resistance wires V Fig. 1.1 (a) (i) • Switch on. Place the sliding contact S on the resistance wire AB at a distance l = 0.200 m from point A. • Measure and record in Table 1.1 the current I in the circuit and the potential difference (p.d.) V across the length l = 0.200 m of resistance wire AB. • Calculate the resistance R of the length l = 0.200 m of resistance wire AB, using the V equation R = . Record R in the table. I • Repeat the procedure using the distance l = 0.400 m. Switch off. • Complete the column headings in the table. Table 1.1 l / V / I / R / 0.200 0.400 [4] (ii) Calculate the difference between the two values for R. difference = .......................................................... [1] (b) (i) • Switch on. Place the sliding contact S on the resistance wire AB at a distance l = 0.500 m from point A. • Measure and record the current I1 in the circuit and the potential difference V1. I1 = ............................................................... V1 = ............................................................... • Calculate the resistance R1 of the length l = 0.500 m of resistance wire AB, using V1 the equation R1 = . I1 R1 = .......................................................... [1] (ii) Use the short connecting lead provided to connect points B and D. • Switch on. Place the sliding contact S on the resistance wire AB at a distance l = 0.500 m from point A. • Measure and record the current I2 in the circuit and the potential difference V2. I2 = ............................................................... V2 = ............................................................... Calculate the combined resistance R2 of resistance wires AB and CD, using the V2 equation R2 = . I2 R2 = .......................................................... [2] (c) Use the results in (b)(i) and (b)(ii) to compare the resistance R1 of wire AB with the resistance R2 of wires AB and CD connected together. Tick one box next to the description that most closely matches your results. R1 = R2 R1 = 2R2 2R1 = R2 There is no simple relationship between R1 and R2. [1] (d) Suggest two reasons why different students all carrying out this experiment carefully, with the same apparatus, may not obtain identical results. 1. ............................................................................................................................................... ................................................................................................................................................... 2. ............................................................................................................................................... ................................................................................................................................................... [2] [Total: 11]

Mark scheme: 1(a)(i) V values to at least 1dp and < 3 V 1 I values to at least 2 dp and < 1 A 1 R values correct and to 2/3 consistent s.f. 1 m, V, A, Ω 1 1(a)(ii) correct difference 1 1(b)(i) potential difference, current and resistance values present with R1 > final value in table 1 1(b)(ii) new set of values present and sensible 1 R1 = 2 × R2 ± 10% 1 1(c) to match results 1 1(d) different heating effects on wires different interpolation of readings between marks on meters difficult to measure length of wire to nearest mm/to judge the position of the sliding contact cell may run down/power of cell may be less Any 2 × 1 mark each 2 Total: 11

More questions on Electrical quantities

2 In this experiment, you will investigate the principle of moments. Carry out the following instructions, referring to Fig. 2.1. a b metre rule P Q 45.0 cm mark bench 5.0 cm mark pivot Fig. 2.1 (a) Place the load P on the metre rule at the 5.0 cm mark. Place the metre rule on the pivot at the 45.0 cm mark. Place load Q on the rule and adjust its position so that the metre rule is as near as possible to being balanced. • Record, in Table 2.1, the distance a between the centre of load P and the pivot. • Measure and record in the table the distance b from the centre of load Q to the pivot. • Repeat the steps above, placing the load P at the 10.0 cm mark, 15.0 cm mark, 20.0 cm mark and 25.0 cm mark. Keep the pivot at the 45.0 cm mark each time. Record all the readings in the table. Table 2.1 a / cm b / cm [2] (b) Plot a graph of b / cm (y-axis) against a / cm (x-axis). Start both axes at the origin (0,0). [4] (c) A student suggests that a is directly proportional to b. State whether your readings support this suggestion. Justify your answer by reference to the graph line. ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[1] (d) (i) • Use the balance provided to measure the mass m, in grams, of the metre rule. m = ............................................................ g • Calculate the value of mX, where X = 0.05 N cm / g. mX = ................................................. N cm [1] (ii) • Use the value of a in the first row of Table 2.1 to calculate Pa, where P = 1.00 N. P is the weight of load P. Include the unit. Pa = ............................................................... • Use the value of b in the first row of Table 2.1 to calculate Qb, where Q = 0.80 N. Q is the weight of load Q. Include the unit. Qb = ............................................................... [2] (e) A student states that Pa should be equal to Qb. Look carefully at Fig. 2.1 and your answers to (d) and suggest what the student has not realised. ................................................................................................................................................... ...............................................................................................................................................[1] [Total: 11]

Mark scheme: 2(a) a values 40 cm, 35 cm, 30 cm, 25 cm, 20 cm 1 b values all less than 50 cm and decreasing 1 2(b) Graph: axes correctly labelled 1 suitable scales 1 all plots correct to ½ small square 1 good line judgement, thin, continuous line 1 2(c) expect NO. line does not pass through origin 1 2(d)(i) mass 50 g to 200 g and mX seen 1 2(d)(ii) calculations correct 1 Qb + mX must be between 36 and 40 inclusive 1 2(e) not taken the weight of the rule/moment of the weight into account/the pivot is not at the centre of the rule 1 Total: 11

More questions on Forces

3 In this experiment, you will investigate the refraction of light passing through a transparent block. Carry out the following instructions, using the separate ray-trace sheet provided. You may refer to Fig. 3.1 for guidance. hole F N A B E M D C L eye ray-trace sheet Fig. 3.1 • 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 the outline of the block ABCD. • Remove the block and draw a normal NL at the centre of side AB. Label the point E where the normal crosses AB. Label the point M where the normal crosses CD. (a) • Draw a line FE to the left of the normal, and at an angle of incidence i = 40° to the normal, as shown in Fig. 3.1. • Place two pins P1 and P2 on the line FE, placing one pin close to E. Label the positions of P1 and P2. • Replace the block and observe the images of P1 and P2 through side CD of the block so that 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 and P4, and the images of P1 and P2 seen through the block, appear one behind the other. Label the positions of P3 and P4. Remove the block. [2] (b) • Draw a line joining the positions of P3 and P4. Continue the line until it meets the normal NL. Label the point K where this line crosses CD. • Measure and record the angle α between the line joining the positions of P3 and P4 and the normal NL. α = ............................................................... • Measure and record the length x between points M and K. x = ............................................................... [3] (c) • Repeat the steps in (a) but with the line FE to the right of the normal. • Draw a line joining the new positions of P3 and P4. Continue the line until it meets the normal NL. Label the point Q where this line crosses CD. • Measure and record the angle β between the line joining the new positions of P3 and P4 and the normal NL. β = ............................................................... • Measure and record the length y between points M and Q. y = ............................................................... [3] (d) A student suggests that the results for α and x should be the same as the results for β and y. State whether your results support this suggestion. Justify your answer by reference to the results. statement .................................................................................................................................. justification ................................................................................................................................ ................................................................................................................................................... [2] (e) Suggest one precaution that you should take with this experiment to obtain reliable results. ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[1] Tie your ray-trace sheet into this Question Paper between pages 8 and 9. [Total: 11]

Mark scheme: 3(a) ray-trace: normal in centre of AB and CD (by eye) and FE at 40° to normal 1 first P1 P2 distance at least 5 cm 1 3(b) P3 P4 line correctly drawn 1 α correctly measured to ± 2° 1 x correct to 2 mm 1 3(c) α and β values 38 – 42 1 correct units for x and y 1 all lines present and in approximately correct positions and neat 1 3(d) statement matches readings (expect YES) 1 justification to include the idea of within (or beyond, ecf) the limits of experimental accuracy 1 3(e) any one from: large pin separation/pins must be >5 cm apart ensure pins vertical/upright/perpendicular to the paper view bases of pins use thin pencil lines/thin pins 1 Total: 11

More questions on Light

4 A student is investigating the effect of draughts (moving air) on the rate of cooling of hot water. The following apparatus is available: electric fan with four speed settings supply of hot water thermometer 250 cm3 beaker 250 cm3 measuring cylinder stopwatch clamp, boss and stand. Plan an experiment to investigate the effect of draughts on the rate of cooling of hot water. You are not required to carry out this investigation. You should: • explain briefly how you would carry out the investigation • state the key variables that you would control • draw a table, or tables, 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 readings to reach a conclusion. You may draw a diagram if it helps your explanation. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[7] [Total: 7]

Mark scheme: 4 method to include: MP1 measurements of temperature of hot water over a period of time/measurement of temperature at start and end of a specified cooling time/measurement of time for a specified temperature drop 1 MP2 repeat using variety of fan speeds (blowing air over water surface) 1 MP3 MP4 two from: room temperature initial temperature of hot water volume/mass/amount of hot water distance of beaker to fan for each speed setting time of cooling temperature drop 2 MP5 table with columns for fan speed, time and temperature with units 1 MP6 compare readings to find which fan speed produces the greatest temperature drop/takes least time/plot a graph 1 MP7 in the same time/for the same temperature drop/compare slopes 1 Total: 7

More questions on Transfer of thermal energy