BTYSS 2024 FYE 4E PHY MS

`1 Beatty Sec 4E Preliminary Examination 2024 Physics 6091 Beatty Sec 4E Physics (6091) Paper 1 and Paper 2 Preliminary Examination 2024 MARKING SCHEME Paper 1 [40 marks] 1 C 2 D 3 A 4 A 5 C 6 C 7 C 8 D 9 D 10 D 11 A 12 D 13 B 14 B 15 C 16 C 17 D 18 A 19 B 20 B 21 A 22 A 23 D 24 A 25 A 26 D 27 C 28 C 29 D 30 C 31 D 32 D 33 C 34 B 35 B 36 D 37 D 38 B 39 B 40 C Minus 1 for missing/wrong unit and minus 1 for wrong s.f [Max minus 2 for whole paper] Paper 2 Section A [70 marks] Qn Answer Mark 1a The force exerted by the mercury on the trapped air changes when the tube is rotated, causing the pressure exerted by the mercury on the trapped air to change. 1 1b Pliquid = ρgh = 14000 × 10 × (30 ÷ 100) = 42000 Pa Pgas = 42000 + 1.0 × 105 = 142000 Pa ≈ 140000 Pa (2 s.f) 1 1 1c 1.0 × 105 Pa 1 2a • When temperature increases, the pressure of the gas inside the elastic flask increases and the force exerted on the walls of the flask increases. • The elastic flask expands and the volume of the gas increases, leading to a decrease in the pressure of gas. 1 1 2b • When the temperature increases, the average kinetic energy of the particles increases. • The particles move faster (average velocity increases) and collide with the walls of the flask more frequently and vigorously. • The average force exerted on the walls increases and since P = F / A, the pressure of the gas increases. 1 1 1 3a Qheater – Qsurroundings = Qheating + Qboiling (1.0 × 103)t – 20t = (1.5)(4200)(100 – 25) + (0.050)(2.26 × 106) 980t = 585500 t = 597 s ≈ 600 s (2 s.f) 2 1 3b • The air above the hot water is heated and expands. • The heated air is less dense and rises while the cooler surrounding air which is denser sinks to replace it. • The cooler air is then heated by the hot water and the process repeats to remove energy from the hot water. 1 1 1 4a Converging / Convex 1 4b • When ray R enters, it moves from the optically less dense air to optically denser glass. • The speed of light decreases and the ray bends towards the normal. • When ray R exits, it moves from the optically denser glass to optically less dense air and the speed of light increases, causing the ray bends away from the normal. 1 1 1

`2 Beatty Sec 4E Preliminary Examination 2024 Physics 6091 4c Either emergent ray R or the ray through F extended to the left of the lens Both ray through F and R shown and image marked at intersection of extended rays 1 1 4d • The image forms further away from the lens. • The image becomes larger. 1 1 5a Direction of field lines Electric field pattern 1 1 5b I = Q / t = (4.8 × 10-9) ÷ (2.0 × 10-3) = 2.4 × 10-6 A 1 1 6a P = I2R = (0.0020)2(800)