2023 Physics Prelim Paper 3 Mark Scheme

14 August 2023 1 hour 50 minutes Anglican High School Secondary Four Preliminary Examination 2023 CLASS CLASS INDEX 4 Anglican High School 2023_S4_Prelim_PHY_P3 [Turn over S4 This document consists of 12 printed pages.

1 In this experiment, you will investigate the mass and volume of a brass mass. You are provided with: • a brass mass Note: Deduct max 1m for precision error(s) and max 1m for unit error (s) • a ruler • two set squares • an electronic balance (a) (i) Describe one precaution you must take before measuring the mass of the brass mass using an electronic balance. …Press the ‘0’ or tare button to ensure that the initial reading is 0.00 g. ………. [1] (ii) Measure and record the mass of the brass mass. Between 99.00 g to 101.00 g (to 2 d.p.) mass = ……………………………. [1] (b) (i) Draw a labelled diagram to show how to use the ruler and the set squares to measure the diameter of the brass mass. correct use of set squares (to determine the boundary of the diameter) and use of rule to measure the diameter [1] (Note: The 30-cm ruler’s zero mark is not at the edge. Not all set squares have the zero mark at the edge) correct labelling of mass, set squares and ruler [1] (provided the set-up is correct) (ii) Measure and record the diameter d of the brass mass. d = 2.5 cm to 2.7 cm to 1 d.p.[1] d = ……………….………. [1] 2 Section A ruler set squares diameter

(c) (i) Measure and record the total length l of the brass mass, as shown in Fig. 1.1. 2.8 cm – 3.4 cm [1] in 1 d.p Fig. 1.1 (not to scale) l = ………………………….. [1] (ii) Estimate the volume V of the brass mass using the equation 𝑉 = 𝜋 4 𝑙𝑑2 Correct calculations with correct units (cm3) [1] (14 to 19 cm3) V = ……………………….… [1] (iii) The volume calculated in (c)(ii) is an estimate of the volume of the brass mass. Explain why it is only an estimate and whether it is a good or poor estimate of the actual volume of the brass mass. Why it is an estimate: length included spaces occupied by air / uneven diameter throughout the length [1] Why it is a poor estimate: Poor estimate of actual volume of brass mass as the volume of air is of a significant percentage of volume calculated in c(ii) / the difference was very large compared to the total volume [1] (iv) Describe how the method for determining the volume of the brass mass may be improved. Use displacement method to find volume of brass mass from the change in volume of water in measuring cylinder [1] Or Measure volume of water displaced from a Eureka can when mass is placed inside [1] Or Using formula, density = mass / volume, determine volume with density of brass and mass known. [1] Or Measuring the dimensions of the main body and the protrusion separately, then calculate the individual volumes before adding them together 3 Anglican High School 2023_S4_Prelim_PHY_P3 [Turn over l

2 In this experiment, you will investigate the deviation of a ray of light passing through a glass block. You are provided with Note: Deduct max 1m for precision error(s) and max 1m for unit error (s) (a) Fig. 2.2 is on page 5 of your question paper. On Fig. 2.2, (i) draw a normal to the line XY at point M, above and below the line XY, (ii) draw a line from M at an angle of 60o to the normal towards the top left edge of the page. Label this line L. (iii) Extend this line from M to the bottom right edge of the page. Label this line K. Met all requirements (i) – (iii), lines L and K need not reach the edges of page [1] (b) Place the block on Fig. 2.2, with one of its long sides on the line XY. The top left-hand corner of the block should be at X, as shown in Fig. 2.1. Fig. 2.1 (c) (i) On Fig. 2.2, draw the outline of the block. (ii) Position the illuminated slit so that a ray of light passes along line L from the top left edge of the page towards M. (iii) On Fig. 2.2, mark and label two points P1 and P2 on the ray that leaves the block. You should choose the position of these two points so that the position of the ray can be accurately drawn. Show refraction on lower surface of glass block in the correct direction & points P1 and P2 should be at least 5.0 cm apart. [1] (d) (i) Remove the block. Draw a line through P1 and P2 to touch the outline of the block at a point. Label this point N. (ii) Draw a straight line from M to N and measure the length l of the line MN. . correctly determined from the drawing and answer to 1 d. p. (allow for ecf) l = e.g. 7.6 cm….. [1] (iii) Measure the perpendicular distance d between the line K and the line through P1 and P2. correctly determined from the drawing and answer to 1 d. p. d = e.g. 3.5 cm [1] (iv) Calculate 𝑑 𝑙 . correct calculation with no units [1] 𝑑 𝑙 = ……………………… [1] Anglican High School 2023_S4_Prelim_PHY_P3 4 block X Y M

Fig. 2.2 5 X M Y Anglican High School 2023_S4_Prelim_PHY_P3 [Turn over

(e) A student claims that the value of 𝑑 𝑙 is linearly related to θ, the angle the ray of light from the illuminated slit makes to the normal. Using the same apparatus, plan an experiment to find out if the student’s claim is correct. Your plan should include • a list of quantities that you should keep constant, • a detailed description of how you will perform the experiment, • a statement of the graph that you would plot to test the relationship, • a sketch of the graph that you would obtain if the suggested relationship is correct. Variables mentioned anywhere in the answer: Constant variables (at least 2) [1] - point at which the light ray is incident on the glass block / light ray must pass through M - orientation of glass block (largest face down) / always place glass block on outline drawn) Independent variable – angle of incidence at M, θ Dependent variable – value or ratio of 𝑑 𝑙 Steps: 1. Set up the apparatus as shown in Fig. 2.1 with angle θ at 60 o (any logical starting angle) at point M. 2. Determine the values of d, 𝑙 and 𝑑 𝑙 as described in steps 2(b) to 2(d) on page 4 of the question paper. [Steps 1 & 2 [1]] 3. Repeat steps 1 – 2 for 5 more sets of readings by varying angle θ. [1] Make sure that the light ray pass through M and that the glass block is placed on the outline with the largest face down. (This sentence emphasizes the variables to be kept constant). 4. Tabulate all readings. 5. Plot a graph of 𝑑 𝑙 against θ. [1] Correct sketch of graph with 𝑑 𝑙 as vertical axis and θ as horizontal axis with c ≠ 0 (non-zero y-intercept) [1] [Total: 10] Anglican High School 2023_S4_Prelim_PHY_P3 6

OR: 1. Set up the apparatus as shown in Fig. 2.1 with angle θ at 60 o (any logical starting angle) at point M. Draw line L along this angle to the top left edge of page. Extend this line to the bottom right edge of the page and label it K. 2. Position the illuminated slit so that a ray of light passes through the glass block at 60 o along