beatty BTYSS 4E5N ScPhy PRELIM 2020 QP1 _ QP2 MScheme

1 BEATTY SECONDARY SCHOOL PRELIMINARY EXAMINATION 2020 MARKING SCHEME SUBJECT : SCIENCE (PHYSICS) LEVEL : Sec 4E/5N PAPER : 5076 / 1 & 2 SETTER : Mrs Seah-Pay Ling Ling PAPER 1 [40 marks] (Q1-20 for science physics) 1 2 3 4 5 6 7 8 9 10 C B D B D A D B C B 11 12 13 14 15 16 17 18 19 20 D D B B B D D C D B PAPER 2 [65 marks]  Deduct ½ mark for wrong units from overall score (max 1 mark)  Deduct ½ mark for wrong significant figures from overall score (max 1 mark) Section A [45 marks] marks Remarks 1 Choice of suitable scale, 1.0 cm represents 0.010 N. This mark to be awarded only if students proceed to draw a diagram. Smallest diagram acceptable: 1.0 cm rep 0.0125N Both magnitude and direction of Electric force and Weight are correctly drawn Tension in the acceptable range of 0.158 N +/1 mm of students’ scales  in the acceptable range from 70 to 73 and recorded to the nearest degrees to be measured not calculated  If all wrong but the general shape of right-angled triangle drawn – 1m 1 1 1 1 4

2 2 (a) a = (18-10)/(12-5) = 1.14 m/s2 1 1 (b) Total distance = (10)(5) + (0.5)(10+18)(7) +(18)(6) = 256 m Average speed = 256/18 = 14.2 m/s 1 1 (c) From t = 5 to 9.4 s, distance between lorry and car increases (since the car is slower). From t = 9.4 s to 12 s, distance between lorry and car decreases. (since the car is now faster than lorry). Note: Car is still behind lorry. 1 1 6 3 (a) The particles in the steel nearer to the heat source gained kinetic energy and vibrate more vigourously. The free electrons gained kinetic energy and moved more quickly. They collide with adjacent particles and pass their kinetic energy to them. 1 1 (b) (i) F= 80 N 1 1 (ii) weight = 12.5 N 1 (iii) (M x 10 x 0.8) + (12.5 x 0.5) = 80 x 0.3 M = 2.22 kg Ecf from 4ci and 4cii. 1 1 7 4 (a) As air is bubbled into the beaker, it causes the alcohol to evaporate. Energy is absorbed from the water on the table for the alcohol to change into gaseous state. So the water loses energy and start to freeze. 1 1 (b) Energy is absorbed to overcome the intermolecular forces of attraction. It is not used to increase kinetic energy / molecular speed thus temperature remains constant. 1 1 4 5 (a) v = f × λ 300,000,000 = 2500,000,000 × λ λ = 0.120 m 1 1 (b) Satellite communication / weather radar / long distance telecommunication / GPS / mobile phoes (* accept any of the application if it is in the communication field. 1 1 (c) Microwave is a transverse wave but ultrasound is a longitudinal wave. Microwave does not need a medium to transmit but ultrasound requires a medium. (accept any reasonable differenc