ACS Exp Prelim 2024 P3 MS final

This document consists of 13 printed pages PRELIMINARY EXAMINATION 2024 YEAR 4 EXPRESS PHYSICS 6091 / 03 Tuesday 30 July 2024 1 hour 50 minutes READ THESE INSTRUCTIONS FIRST Write your index number and name on all the work you hand in. Write in dark blue or black pen. You may use an 2B pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions. All of your answers should be written in this Question Paper: scrap paper must not be used. Graph paper is provided in this Question Paper. Additional sheets of graph paper should be used only if it is necessary to do so. You will be allowed to work with the apparatus for a maximum of 55 minutes for each section. You are expected to record all your observations as soon as they are made. An account of the method of carrying out the experiments is not required. The use of an approved scientific calculator is expected, where appropriate. 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. Index Number Name For Examiner’s use 1 2 3 Total

Y4Exp Physics Preliminary Examination 2024 Page 2 of 13 Section A 1 In this experiment, you will deduce the path taken by a light ray undergoing total internal reflection in a glass block. You are provided with: • A4 Plain Paper • Cork mat • Five optical pins • Rectangular glass prism • Protractor • 30.0 cm ruler • Set square Fig. 1.1 (not to scale) 1.0 cm 12 points: any 3 for 1m 1. Trace of block (labelled ABCD) 2. Normal 1.0 cm from corner B 3. Incident ray drawn and actually 30° 4. P1 and P2 are marked and labelled 5. P3 and P4 are marked and labelled 6. Pins are 5 cm apart 7. Emergent ray is drawn 8. N is labelled 9. X distance matches calculations 10. O is labelled 11. Transmission rays are drawn 12. Normal at N and angle e is correct if numerically labelled *** Accuracy: [deduct 1m for accuracy] • r = 18° ± 2 (16-21°) • e = 30° ± 3 if normal is not actually 90° , this affects subsequent measurements.

Y4Exp Physics Preliminary Examination 2024 Page 3 of 13 (a) Place the largest surface of the block in the middle of the sheet of plain paper. Draw around the block to mark its position. Remove the glass block and label the corners ABCD as shown in Fig. 1. Draw a normal at M, 1.0 cm from the corner of the block, as shown in Fig. 1. Use the protractor to construct an incident ray at an angle of incidence i of 30o. Replace the block and place the plain paper on the cork mat. Stick two object pins P1 and P2 along the incident ray. Position your eyes to look through side CD of the glass block, at side BD of the glass block. You should observe 2 reflected images of P1 and P2 appear at side BD when looking through side CD. Place two further pins P3 and P4 in line with the reflected images of P1 and P2 so that, when viewed through the block, the four pins appear to be one behind the other. Remove the block and draw a line joining P4 and P3 to the edge of the block. This is the emergent ray. Mark the point where the emergent ray exits the block as N. Measure and record the distances BD and ND from your trace using the ruler. BD = ......................................................... [1] ND = ......................................................... [1] (b) (i) Calculate the value of x, using the equation 𝒙 = 𝑩𝑫 𝑵𝑫+𝟏.𝟎 × 1.0 𝑐𝑚 , where BD and ND are expressed in metres. x = ......................................................... [1] (ii) At a distance of x below corner B of the block, mark out the point O on side BD, as shown in Fig. 1. Draw straight lines from M to O, and O to N to represent the path taken by the incident ray after entering the block. Measure the angle of refraction r inside the block. r = ......................................................... [1] Mark for instrument’s precision and unit (1 d.p. & cm) Mark for correct working, answer, s.f. (2 s.f.) Mark for instrument’s precision and unit. (nearest whole number & ° , must be accurate to trace ±1°)

Y4Exp Physics Preliminary Examination 2024 Page 4 of 13 (c) State 2 precautions you took to improve the accuracy of the experiment. 1 ……………………………………………………………………………………… ……………………………………………………………………………………… 2 ……………………………………………………………………………………… ……………………………………………………………………………………… [2] (d) Comment on the relationship between the angle of incidence, i, and the angle of emergence, e, based on your experiment. ……………………………………………………………………………………….. ……………………………………………………………………………………….. [1] (e) Submit your trace together with this answer sheet at the end. [4] 1. Pins are placed at least 5 cm apart, to reduce uncertainty when aligning the pins, and determine a more accurate path travelled by the incident ray. This will give a more accurate r value. 2. Pins are inserted vertically into the corkboard, so that when aligning the pins to determine the path of the incident ray, the alignment matches the constructed light ray on the paper more accurately, giving a more accurate r value. 3. Place my eyes level with the glass block and when performing alignment of the pins, to avoid parallax error and to obtain a more accurate r value. 4. When drawing the outline of the block, I ensure my eye was vertically level with the flat sides of the block when drawing the trace (block was not a perfect cuboid) to avoid parallax error. 5. When aligning the images and pins, I moved my eye rather than rotate the mat to avoid any movement that may accidentally cause the block to shift from its original position. From my experiment, i and e are equal in magnitude / to each other. OR From my experiment, i and e are very close to each other in value. Ecf from diagram (either based on the labelled angle, or within 1 degree of e) Refer to Fig. 1.1

Y4Exp Physics Preliminary Examination 2024 Page 5 of 13 2 In this experiment, you will investigate the current in a circuit where a fixed resistor and variable resistor arranged in parallel. You are provided with: • a battery • a switch • an ammeter • a voltmeter • a length of resistance wire mounted on a metre rule • connecting leads • a resistor labelled R • a jockey. Fig. 2.1 Set up the apparatus as shown in Fig. 2.1. The jockey can be connected at different points along the length of the resistance wire. Connect the jockey to the wire at the 50.0 cm mark of the ruler. Close the switch. (a) With the jockey still connected in this position, (i) Record the length, L, from the 0.0 cm mark of the metre rule to the position of the jockey on the wire, in metres. L = ..................................................... m [1] (ii) Record the reading of current on the ammeter, I. I = ......................................................... [1] Mark for instrument’s precision and unit, 0.500 ± 0.020 m (3 d.p., m) Mark for instrument’s precision and unit (0.40 – 1.00 A) (2 d.p., A)

Y4Exp Physics Preliminary Examination 2024 Page 6 of 13 (b) Open the switch. Disconnect the jockey from the resistance wire. Connect the voltmeter across the two ends of the battery. Record the reading of electromotive force (e.m.f.) on the voltmeter, V. V = ......................................................... [1] (c) Calculate the value of 1/L. 1/L = ......................................................... [1] (d) Quantities I and L are related by the equation 𝐼 = 𝑉 𝐿 × 𝑅𝑤 + 𝑉 𝑅1 where I is the cu