SAJC 2022 Physics Practical Prelim H2 P4 for sharing

1 SAJC Prelims 2022 9749/04 Class Index Number Name 21S ST. ANDREW’S JUNIOR COLLEGE JC 2 2022 Preliminary Examination PHYSICS, Higher 2 9749/04 Paper 4 Practical 15 August 2022 2 hours 30 minutes Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. READ THESE INSTRUCTIONS FIRST Write your name, index number and Civics Group in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. Answer all questions. Write your answers in the spaces provided on the question paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Give details of the practical shift and laboratory where appropriate in the boxes provided. 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. This document consists of 20 printed pages and 2 blank pages. For Examiner’s Use 1 /11 2 /11 3 /20 4 /13 Total /55 Shift Laboratory Shift Laboratory

2 SAJC Prelims 2022 9749/04 1 In this experiment, you will investigate the centre of gravity of a suspended card shape. (a) You have been provided with a card shape, as shown in Fig. 1.1. Fig. 1.1 Measure and record the lengths b and c. b =……………………………………. c =……………………………….…… [1] (b) Use the pin to make two small holes in the card, as shown in Fig. 1.2. Fig. 1.2

3 SAJC Prelims 2022 9749/04 Suspend the card as shown in Fig. 1.3. The pin should be held firmly in the clamp and the card should hang freely. The loop of string at the end of the pendulum should be attached to the pin. Fig. 1.3 Use the pencil to draw a line on the card along the path of the string in Fig.1.3, as shown in Fig.1.4. Fig. 1.4 Repeat the procedure using the other hole in the card. The two lines will cross at the centre of gravity G, a distance y above the longest edge of the card, as shown in Fig.1.5. Fig. 1.5 Measure and record y. y =……………………………….……[2]

4 SAJC Prelims 2022 9749/04 (c) (i) Reduce c by 6 cm by cutting the card at right-angles to its longest edge. Measure and record c. c = ………………………………[1] (ii) Repeat the procedure from page 3. y = ………………………………[1] (d) Theory suggests that 𝑦 = 𝑏2 2 +𝑏𝑐 8 𝑏+𝑐 2 where b remains constant. (i) Calculate the value of y when c is reduced by another 6 cm. y = ………………………………[1] (ii) The experiment is repeated for more values of c. State the graph to plot to obtain a straight line assuming that the theory is correct. ............................................................................................................................ ............................................................................................................................ ........................................................................................................................[1] (iii) State expressions for the gradient and y-intercept of the line. gradient = …………………………………….. y-intercept =…………………………………[2]

5 SAJC Prelims 2022 9749/04 (iv) Explain, without calculation, why the value of y is equal to 6 cm when c = 0. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ........................................................................................................................[2] [Total: 11]

6 SAJC Prelims 2022 9749/04 2 In this experiment, you will investigate an electrical circuit. (a) Set up the circuit shown in Fig. 2.1. Fig. 2.1 The value of the resistance of Y is RY. Its value should be 10 Ω. Record RY. RY = …………………………………. Close the switch. Measure and record the ammeter reading I1. I1 = ………………………………….

7 SAJC Prelims 2022 9749/04 Open the switch. Change the positions of the resistors Y and X, as shown in Fig. 2.2. Fig. 2.2 Close the switch. Measure and record the ammeter reading I2. I2 = …………………………………. Open the switch. [1]

8 SAJC Prelims 2022 9749/04 (b) Vary RY and repeat (a). Present your results clearly. [3] (c) I1, I2 and RY are related by the expression 𝐼1 𝐼2 = 𝑅𝑌 2𝑅𝑋 + 1 2 where RX is the resistance of resistor X. Plot a graph and use the gradient to determine RX. Rx = ……………………………………..….. [5]

9 SAJC Prelims 2022 9749/04

10 SAJC Prelims 2022 9749/04 (d) By considering the value of 𝐼1 𝐼2 when RY = RX, describe another way in which the graph can be used to determine RX. ……………………………………………………………………………………………......... ……………………………………………………………………………………………......... ……………………………………………………………………………………………........[1] (e) The experiment is repeated with a larger value of RX. Sketch a line on your graph grid on page 9 to show the expected result. Label this line W. [1] [Total: 11]