NHHS 2025 PHY PRELIM P3 QP

This paper consists of 15 printed pages. Name: _____________________________________ ( ) Class: Sec 4 / ( ) NAN HUA HIGH SCHOOL PRELIMINARY EXAMINATIONS 2025 Subject : Physics Paper : 6091/3 Level : Secondary Four Date : 12 August 2025 Duration : 1 hour 50 minutes INSTRUCTIONS TO CANDIDATES Write your name, class and register number in the spaces at the top of this page and on any separate answer paper used. 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 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 these observations are made. An account of the method of carrying out the experiment is not required. The use of 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. Shift Laboratory For Examiner’s Use 1 2 3 Total

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 2 of 15 Section A 1 In this experiment you will investigate the deviation of a ray of light that is reflected internally from the surface of a rectangular transparent block. You are provided with: • a transparent block • Light source with slit, • 30-cm ruler, • protractor, • an A4 paper (a) (i) Measure the length (L), width (W) and height (H) of the transparent block using the 30 cm ruler. L = W = H = [1] (ii) Given that the mass of the glass block is 416 g. Calculate the density of the glass block. density = [2]

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 3 of 15 (b) Fig. 1.1 On Fig. 1.2 on page 5 of your question paper, Trace the outline of your glass block and label it PQRS as above. Align the short side QR along the dotted line. Mark a point B on edge PQ at 20 mm from Q. Draw a dotted line at B perpendicular to PQ and label it N to represent the normal. Draw a line which makes an angle of incidence (i) of 40 ° with the normal. (i) Measure and record i. i = [1] Place the glass block onto the outline marked PQRS. Turn on the light source to illuminate the slit. Position the illuminated slit so that a single ray of light is along the line.

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 4 of 15 The light ray will emerge from the edge SR of the glass block as shown in the diagram. You may use the A4 paper provided shade the diagram (to block the ambient light in the room) if the emergent ray is not clear enough. Mark two points P3 and P4 on the emergent ray. Remove the glass block and draw a straight line passing through P3 and P4 till it intersects with side SR at point D. Extend this line with dotted line. (See diagram) Extend the line AB with a dotted line until it intersects with the dotted line you have drawn earlier. (ii) Measure and record the angle θ between BC and DC and the perpendicular distance (x) between C and face QR θ = [1] x = [1] (c) State two precautions which you took to ensure the experiment was performed as accurately as possible. [2] (d) Identify two sources of error which make the measurements taken to be inaccurate. [2] [Total: 10]

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 5 of 15 Fig. 1.2

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 6 of 15 Blank Page

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 7 of 15 2 In this experiment, you will investigate an electric circuit containing a light-dependent resistor (LDR). You are provided with: • a lamp, • a light-dependent resistor with blue tack, • a power supply, • a fixed resistor of resistance 470 Ω, • a ruler, • a stand and boss, • a switch, • a voltmeter and two connecting leads • 6 connecting leads. (a) Set up the circuit as shown in Fig. 1.1. Fig. 2.1 (b) Set up the light-dependent resistor (LDR) and lamp as shown in Fig. 2.2. Secure the light bulb to the boss above the LDR. The boss can be moved up and down to change the distance between the LDR and the lamp. Set distance d to approximately 2.0 cm. Fig. 2.2 bench d LDR Light Bulb Retort Stand Boss

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 8 of 15 (i) Measure the distance d. d = [1] (ii) State one difficulty when making this measurement. [1] (c) (i) Connect the voltmeter across the terminals of the power supply. Close the switch. Record the voltmeter reading VS. VS = (ii) Connect the voltmeter across points A and B. Close the switch. Record the voltmeter reading VAB. VAB = [1] (iii) Open the switch. The current I in the fixed resistor is given by the equation 𝐼𝐼 = 𝑉𝑉𝐴𝐴𝐴𝐴 𝑅𝑅 Where R = 470 Ω. Calculate I. I = [1]

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 9 of 15 (iv) Calculate the resistance RL of the LDR using the equation 𝑅𝑅𝐿𝐿 = 𝑉𝑉𝐿𝐿 𝐼𝐼 Where the potential difference (p.d.) VL across the LDR is given by VL = (VS – VAB). RL = [1]

Nan Hua High School Preliminary Examinations 2025 Physics 6091/3 Page 10 of 15 (d) A student who is investigating the relationship between the resistance of the LDR and the distance from the LDR to the light source, claims that the relationship should be RLDR = 2𝛾𝛾𝛾𝛾 + k where RLDR is the resistance of the LDR, d is the distance from the light source, k and 𝛾𝛾 are constants. Plan an experiment using the above relationship to determine the constant 𝛾𝛾 using a graphical method. Your plan should include • the quantities that you should keep constant, • a detailed description of how you would 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, • an explanation of how you would obtain a value for the constant 𝛾𝛾 from your graph.