Cambridge IGCSE Physics 0625 — 2023 Feb/March Paper 6 · Variant 2

1 A student determines the diameter of a marble by two methods and calculates the density of the material from which the marble is made. Some marbles are shown full size in Fig. 1.1. D bench Fig. 1.1 Method 1 (a) (i) On Fig. 1.1, measure the length D. D = ......................................................... cm Using your value of D, calculate the average diameter d1 of one marble. d1 = ......................................................... cm [2] (ii) Suggest why it is more accurate, when using a ruler, to measure D for five marbles rather than measure the diameter of a single marble. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... [1] Method 2 (b) Fig. 1.2 shows two wooden blocks and one of the marbles. wooden blocks marble bench Fig. 1.2 Describe how the student uses the two blocks and the marble to determine a new accurate value for the diameter of a marble. Draw a diagram to show the arrangement. Describe clearly how the student ensures that the value for the diameter of a marble is as accurate as possible. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] (c) (i) The student uses the top pan balance as shown in Fig. 1.3 to measure the mass of the five marbles. He measures the mass M0 of a beaker without the marbles and then measures the mass M5 of the same beaker containing the marbles. beaker marbles top pan balance bench 30.8 g 64.3 g Fig. 1.3 Record the values of M0 and M5 as shown on the top pan balance in Fig. 1.3. M0 = ............................................................ g M5 = ............................................................ g Use these values to calculate the average mass m of one marble. m = ...................................................... g [1] (ii) The student pours water into a measuring cylinder. He records the reading V1 of the water level in the measuring cylinder. 26 V1 = ........................................................ cm3 The student places the five marbles into the water in the measuring cylinder as shown in Fig. 1.4. measuring cylinder water 40 marbles 30 bench Fig. 1.4 Record the new reading V2 of the water level in the measuring cylinder shown in Fig. 1.4. V2 = .................................................. cm3 [1] (iii) Calculate a value for the average volume V of one marble. Use the values from (c)(ii) and the equation V2 – V1 V = . 5 V = .................................................. cm3 [1] (iv) Calculate a value for the density ρ of the material from which the marble is made. Use your values of m from (c)(i), V from (c)(iii) and the equation m ρ = . V ρ = .............................................. g / cm3 [1] (d) Describe one possible source of inaccuracy in the method described in (c) and suggest one improvement to reduce its effect. source of inaccuracy ................................................................................................................. ................................................................................................................................................... improvement ............................................................................................................................. ................................................................................................................................................... [2] [Total: 11]

Mark scheme: Question Answer Marks 1(a)(i) D = 7.8(cm) 1 d1 = 1.6(cm) 1 1(a)(ii) effect of uncertainties reduced/ 1 diameters of marbles vary 1(b) use marble between two blocks and measure gap 1 suitable means of ensuring accuracy e.g.: 1 measure gap in at least two places and check equal to ensure blocks are parallel / rotate marble to different axis and take average of measurements 1(c)(i) M0 and M5 present and m = 6.7 (g) 1 1(c)(ii) V2 = 38 (cm3) 1 1(c)(iii) V = 2.4 (cm3) 1 1(c)(iv) = 2.8 (g / cm3) 1 1(d) suitable source of inaccuracy: 1 e.g. graduations on measuring cylinder too large / improvement matching source of inaccuracy: 1 e.g. use smaller measuring cylinder or greater number of marbles /

More questions on Density

2 A student investigates the cooling of hot water from different initial temperatures. She uses the apparatus shown in Fig. 2.1. clamp thermometer boss beaker stand bench 30 20 10 Fig. 2.1 (a) (i) The student measures the room temperature. Record room temperature θR shown on the thermometer in Fig. 2.1. θR = .................................................... °C [1] (ii) Describe one precaution that the student takes to ensure that this temperature reading is as accurate as possible. ........................................................................................................................................... ..................................................................................................................................... [1] (b) Experiment A The student pours a volume of 100 cm3 of hot water into the beaker and records the temperature θA at time t = 0 s. She records the temperature of the water in the beaker every 30 s. Her readings for Experiment A are shown in Table 2.1. Experiment B The student repeats the process. She waits until the initial temperature θB of the water is the same value as the temperature θA at 90 s in Experiment A. In the first line of Table 2.1, record her initial temperature θB for Experiment B. [1] Her readings for the remainder of Experiment B are shown in Table 2.1. Table 2.1 t / s θA / °C θB / °C 0 92.0 30 89.5 83.5 60 87.0 81.5 90 85.0 79.5 120 83.5 78.0 150 82.0 76.5 180 80.0 75.0 (c) Write a conclusion stating how the temperature at t = 0 s affects the rate of cooling of the water. Justify your answer by reference to values from the results. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] (d) (i) Calculate the average cooling rate x1 during the second half of Experiment A. Use the readings from Table 2.1 and the equation θA90 – θA180 x1 = T where T = 90 s and θA90 and θA180 are the temperatures at t = 90 s and t = 180 s in Experiment A. Include the unit for the cooling rate. x1 = ......................................................... [1] (ii) Calculate the average cooling rate x2 during the first half of Experiment B. Use the readings from Table 2.1 and the equation θB0 – θB90 x2 = T where T = 90 s and θB0 and θB90 are the temperatures at t = 0 s and t = 90 s in Experiment B. x2 = ......................................................... [1] (iii) A student suggests that x1 and x2 should be the same. State whether your results support this suggestion. Justify your statement by reference to your results. statement .......................................................................................................................... justification ........................................................................................................................ ........................................................................................................................................... ........................................................................................................................................... [2] (e) State two variables which must be controlled so that the comparison of x1 and x2 is valid. 1 ................................................................................................................................................ ................................................................................................................................................... 2 ................................................................................................................................................ ................................................................................................................................................... [2] [Total: 11]

Mark scheme: 2(a)(i) R = 21(.0)(°C) 1 2(a)(ii) view (scale reading) perpendicularly / owtte 1 2(b) B = 85.0 seen in table at t = 0 s 1 2(c) statement matching readings in table 1 comparison of temperature changes over 180 s, matching statement 1 2(d)(i) x1 = 0.056 and x2 present 1 2(d)(ii) unit °C / s 1 2(d)(iii) statement matching results. 1 justification referencing ‘limits of experimental accuracy’ with values quoted 1 2(e) two suitable controls e.g.: 2 same volume of water, same material / thickness / surface area / shape of beaker, same room temp / named appropriate environmental condition

More questions on Transfer of thermal energy

3 A student investigates the properties of a resistance wire. He uses the circuit shown in Fig. 3.1. A crocodile clip resistance wire l Fig. 3.1 (a) On Fig. 3.1, draw a voltmeter connected to measure the potential difference (p.d.) across length l of the resistance wire. [1] (b) (i) The student connects the crocodile clip to a length l = 20.0 cm of the resistance wire. He measures the value of potential difference V and current I for the resistance wire. 2 3 0.4 0.6 1 4 0.2 0.8 0 5 0 1.0 V A Fig. 3.2 Fig. 3.3 Read, and record in the first line of Table 3.1, the values of V and I shown on the meters in Fig. 3.2 and Fig. 3.3. The student repeats the process for lengths l = 40.0 cm, l = 60.0 cm, l = 80.0 cm and l = 100.0 cm of the resistance wire in turn. His results are shown in Table 3.1. Table 3.1 l / cm V / V I / A R / Ω 20.0 40.0 1.7 0.47 3.6 60.0 2.2 0.52 4.2 80.0 2.3 0.35 6.6 100.0 2.4 0.29 8.3 [2] (ii) For length l = 20.0 cm, calculate and record in Table 3.1 the resistance R of the resistance wire. Use your values of V and I from (b)(i) and the equation V R = . I [1] (c) Plot a graph of R / Ω (y-axis) against l / cm (x-axis). Draw the straight line of best fit. [4] (d) (i) Determine the gradient G of the graph. Show clearly on the graph how you obtained the necessary information. G = ......................................................... [1] (ii) The gradient G is numerically equal to the resistance per unit length R0 of the resistance wire. Write down a value of R0 for this experiment. R0 = ............................................... Ω / cm [1] (e) Suggest one practical reason why students carrying out this experiment may not obtain the same readings as in Table 3.1. Assume that the procedure has been done carefully. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [1] [Total: 11]

Mark scheme: 3(a) voltmeter in correct parallel connection and symbol correct 1 3(b)(i) V = 1.3 (V) 1 I = 0.86 (A) 1 3(b)(ii) R = 1.5 () 1 3(c) graph: • axes labelled with quantity and unit 1 • appropriate scales (plots occupying at least ½ grid) 1 • plots all correct to ½ small square and precise plots 1 • well-judged line and thin line 1 3(d)(i) G present and triangle method seen on graph 1 3(d)(ii) R0 in range 0.073 to 0.093( / cm) 1 3(e) any one inherent source of inaccuracy e.g.: 1 difficult to position crocodile clip accurately / inconsistent connection with crocodile clip / resistance wire not uniform

More questions on Electric circuits

4 A student investigates the motion of a ball through the air. Plan an experiment which will enable him to investigate how the range of the ball depends on the angle at which it is launched. The range is the horizontal distance that the ball travels after leaving the end of the channel shown in Fig. 4.1 and before hitting the ground. The apparatus available includes: • a flexible channel, as shown in Fig. 4.1, which can be bent at different angles • a selection of balls, each of different diameter and mass. In your plan, you should: • list any additional apparatus needed • explain briefly how to do the experiment – you may add to Fig. 4.1 if it helps your explanation • state the key variables to keep constant • draw a table 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 results to reach a conclusion. flexible channel variable angle floor Fig. 4.1 .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. .................................................................................................................................................................. ............................................................................................................................................................ [7]

Mark scheme: 4 MP1 apparatus: 1 metre ruler, protractor MP2 method: 1 set initial launch angle roll ball measure range MP3 repeat for different angle 1 MP4 control variable (one from): 1 diameter of ball, mass of ball. angle / height of (upper end of) channel MP5 table: 1 with columns for independent variable and dependent variable (at least) and both with units MP6 analysis: 1 compare readings in a table to see if change in independent variable produces change in dependent variable, plot (line) graph (with axes specified) MP7 additional point (one from): 1 at least 5 sets of data taken, repeat each measurement and take average, means of accurate indication of point at which ball hits floor, clear indication of where to measure range from

More questions on Motion