2025 BTYSS Prelim S4 G2 SP P2 SAK (final)

BEATTY SECONDARY SCHOOL PRELIMINARY EXAMINATION 2025 SECONDARY FOUR NORMAL (ACADEMIC) / G2 CANDIDATE NAME CLASS REGISTER NUMBER SCIENCE (PHYSICS) 5105/02 Paper 2 Structured (Physics) 4 August 2025 Setter: Mr Jerrod Lo Papers 1 and 2: 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and register number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in Section A and any one question in Section B. The use of an approved scientific calculator is expected, where appropriate. In calculations, you should show all the steps in your working, giving your answer at each stage. You are advised to spend no longer than 30 minutes on Paper 1. You may proceed to answer Paper 2 as soon as you have completed Paper 1. At the end of the examination, hand in your answers to Paper 1 and Paper 2 separately. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use A 22 B….. 8 Total 30 This document consists of 15 printed pages and 1 blank page. [Turn over

2 Section A Answer all the questions in the spaces provided. 1 A mobile phone emits and receives four different types of waves, W, X, Y and Z. W, X and Y are electromagnetic waves. When the phone gets warm, it gives off W. The phone receives wireless signals using X, which has higher frequencies than television broadcast waves. The screen emits Y, which lets us see colours. The speakers produce Z, which are longitudinal waves that we can hear. Based on the information, identify the waves W, X, Y and Z. W is …………………………………… X is ……………………………………. Y is ……………………………………. Z is ……………………………………. [2] [Total: 2] speakers W X Y Z screen infra-red radiation microwave sound visible light Any two correct – [1]

3 2 A pile of paper rests on a horizontal surface. The weight of the pile of paper is 27.2 N. (a) Calculate the density of the paper. Use g = 10 N / kg in your calculations. density = ……………… kg / m3 [2] (b) The sheets of paper are uniformly folded in half and restacked to form a new pile on the horizontal surface. Calculate the minimum pressure on the horizontal surface due to the new pile of paper. pressure = ……………… N / m2 [1] [Total: 3] 0.320 m 0.250 m 0.040 m horizontal surface pile of paper P = F ÷ A P = 27.2 ÷ (0.5 × 0.320 × 0.250) P = 680 N / m2 [1] 680 850 W = mg 27.2 = m × 10 m = 2.72 kg [1] d = m ÷ V d = 2.72 ÷ (0.320 × 0.250 × 0.040) d = 850 kg / m3 [1]

4 3 During an earthquake, two types of seismic waves, P-waves and S-waves are produced. The diagram shows the directions of particle vibration in a P-wave and a S-wave as energy is transferred away from the earthquake’s epicentre when viewed from above. (a) State which seismic wave, P-wave or S-wave is a transverse wave. ………………………………………………………………………………………… [1] (b) The foot of a hill is located 6.72 km away from the epicentre. The time taken for a seismic wave to travel from the epicentre to the foot of the hill and reflected back is 3.2 s. (i) Calculate the speed of the seismic wave in metres per second. speed = ……………… m / s [1] (ii) The wavelength of the seismic wave is 875 m. Calculate the frequency of the seismic wave. frequency = ……………… Hz [1] epicentre direction of particle vibration for S-wave direction of particle vibration for P-wave direction of energy transfer 4.8 S-wave [1] 4200 v = d ÷ t v = (6.72 × 1000) ÷ (3.2 ÷ 2) v = 4200 m/s [1] v = f × 𝜆 4200 = f × 875 (e.c.f.) f = 4.8 Hz [1]

5 (c) During an earthquake, a large rock accelerates down the slope of the hill. On the diagram, draw and label arrows to show the directions of the two forces acting on the rock that reduce its acceleration. [1] [Total: 4] 4 At a campfire, water in a ceramic pot is heated until it boils. (a) Describe the change in motion of the particles in the ceramic pot during heating. ………………………………………………………………………………………………. ………………………………………………………………………………………….. [1] (b) Explain the change in arrangement of the water particles during boiling. ………………………………………………………………………………………………. ………………………………………………………………………………………….. [1] [Total: 2] air resistance friction large rock slope of hill both arrows in same direction + correctly labelled – [1] Particles in the ceramic pot vibrate about their fixed positions more vigorously (or faster). [1] Water particles move further apart due to weaker forces of attraction between particles. [1]

6 5 A circuit is made up of a 12 V battery, an ammeter, a 4.0 Ω resistor, a 6.0 Ω resistor and an unknown resistor T. The ammeter shows a reading of 1.6 A. (a) Calculate the total resistance of the circuit. total resistance = ……………… Ω [1] (b) Using your answer in (a), calculate the resistance of resistor T. resistance of resistor T = ……………… Ω [2] [Total:3] A 12 V 4.0 Ω T 6.0 Ω 5.1 7.5 V = R × I 12 = R × 1.6 R = 7.5 Ω [1] Combined R = 1 1 4.0+ 1 6.0 R = 2.4 Ω [1] (e.c.f.) T + 2.4 = 7.5 T = 5.1 Ω [1]

7 6 R is a radioactive material found in a laboratory. The count rate from R is measured by a Geiger-Muller (GM) counter for 24 hours. The table shows the measured count rates every 3 hours for the first 12 hours of the day. The measured count rates do not include background radiation in the laboratory. time / hour 0 3 6 9 12 count rate / counts per minute 72.0 61.0 51.5 43.5 37.0 (a) Using the data in the table, complete the decay curve on the grid to show how the count rate from radioactive material R varies with time. (i) Mark each point between 0 hours and 12 hours with a cross (x). [1] (ii) Draw a best-fit curve that takes into account all plotted points. [1] 0 5 10 15 20 25 10 time / hour count rate counts per minute 20 30 40 50 60 70 80 × × × × 12.5 36 × (b)(i) (a)(i), (a)(ii)

8 (b) (i) Using your graph, determine the half-life of R. Show on the graph how you obtain your answer. half-life = ……………… hours [1] (ii) Using your answer in (b)(i), calculate the time required for R to decay to 12.5% of its original amount. Show your working. time required = ……………… hours [2] (c) R is unstable and undergoes beta-decay. In beta-decay, each nucleus of R ( R29 64 ) gives off one electron ( e-1 0 ) and changes into a stable element Q. (i) Indicate the number of protons and neutrons in a nucleus of Q.