Fuchun Sec 2022 4NA Science Physics Prelim (MS)

Solution for Paper 1 MCQ 1 B 11 D 2 C 12 B 3 B 13 C 4 B 14 A 5 A 15 A 6 A 16 A 7 D 17 D 8 A 18 A 9 C 19 D 10 A 20 D Solution for Paper 2 ECF applies Overall 1 mark deducted if answers are given as a fraction Section A Question Answer Marks Remarks 1 unit symbol multiple of the SI unit (J) joule J 1 kilojoule kJ 1 000/103 gigajoule GJ 1 000 000 000 millijoule mJ 0.001 1 or 2 correct answers -> [1] 3 correct answers -> [2] [2] Did not accept g 2 (a) (b) 3 Lowest CG [1] [1] Most gave 1 as the answer. Most did not use keywords.. they preferred words like middle of the man.

Gave mark as long as they mentioned CG is lower. 3 (a) (b) 550 Ncm The perpendicular distance is different [1] [1] Generally ok. Mark awarded if student attribute to the answer to the distance. Some thought the force was different. Some tried to use GPE to explain. 4 (a) Troughs are in the same phase [1] Poorly done. (b) 2 cm [1] Poorly done. Most did not know that the distance between 2 wavefronts is the wavelength. (c) 1 s [1] Poorly done.

5 (a) 1 mark for correct points 1 mark for best fit curve [2] (b) Accept I = 0.4 A to 0.42 A [1] (c) When potential difference < 1V, resistance is constant OR When current < 0.3A, resistance is constant When potential difference > 1V, resistance is not constant When current > 0.3A, resistance is not constant [1] [1] Most students did not know that the gradient of the I/V graph gives the resistance. Must remind them to use keywords. Total 14 x x x x x

Section B 6 (a) speed = (2xdepth)/time 1500 = (2xdepth)/0.5 depth =375m [1] [1] Most got this wrong as they used the s=d/t formula. (b) echo will take less than 0.5 s OR echo take less time amplitude of echo will be larger OR peak of echo is higher [1] [1] A handful got this correct. Accepted much quicker/faster. Accepted louder. (ci) B B has overcome greater gravitational force OR B has greater/more mass/weight [1] [1] A number got this correct. (cii) PE = mgh = 50x10x50 = 25000J [1] [1] A number got this correct. Total [8] 7 (ai) Magnitude 5N Direction LEFT [1] [1] Most got this right. A handful gave RIGHT as the direction. (aii) F = ma 5 = 2a a = 2.5 m/s2 [1] [1] Most got this correct. (bi) radiation [1] A handful wrote convection. (bii) A Black is a good absorber [1] [1] No marks for good conductor. Any one.. [1]

Total [8] 8 (a) P is connected to wire X R is connected to wire Y [1] [1] Generally ok. Accepted Live Accepted Neutral A number thought R was earth. (b) fuse protects the appliance /limits current to appliance [1] [1] (c) I