2021 J2 H2 Physics Prelim P1 MS Sharing

Anglo-Chinese Junior College 2021 H2 Preliminary Exam Paper 1 Guide H2 (9749) Physics JC2 2020 Page 1 of 4 1 D Depth of swimming pool = 2m Pressure at the bottom of the pool = po + gh = 105 + (103)(10)2 = 107 Pa 2 C 3 C  220 72 3.06 s xxs u t t t       2 2 1 2 10 9.81 3.062 46 m yys u t at   4 B 5 B 6 A    resistive thrust 100 20 2 000 N rel F dmv dt      7 D      20.80 0.30 1.10 m s 70 1.10 77 N 77Apparent difference in mass 7.8 kg9.81 a F m a           8 D

Anglo-Chinese Junior College 2021 H2 Preliminary Exam Paper 1 Guide H2 (9749) Physics JC2 2020 Page 2 of 4 9 C When the string just slackens, the tension in the string is zero. The component of the weight acting in the radial direction provides for the centripetal force.               2 B 2 B 2 2 11 B cos cos 22cos cos 1 5 9 81 71 mvmg r vg r v . rg . . 10 D 11 D 12 D At steady state, pressure in both flasks are the same. Applying ideal gas law 9 PQ QQPP PQ QPP Q P Q PP n RTn RT VV TMV M T V    13 A ( 273.15) ( 273.15) pV nRT pV nR t nRpt V    14 D Heat loss by block of higher temp = Heat gained by block of lower temp 15 ( 35) 30 (95 ) 35 190 2 75 ff ff f Q mc T c T c T TT T         15 C   2 21 22E m f x             2 2 2 2 2110.5 2 3.0 0.40 0.72 222 0.72 m f x m f x E     16 A 17 D 18 A Freq / Hz wavelength / m 9.0 cm tube 13.5 cm tube 5500 0.060 1.50 2.25 7330 0.045 2.00 3.00 7940 0.042 2.17 3.25 11000 0.030 3.00 4.50

Anglo-Chinese Junior College 2021 H2 Preliminary Exam Paper 1 Guide H2 (9749) Physics JC2 2020 Page 3 of 4 19 A 20 C initial final gain in kinetic energy loss in electric p otential energy d 3d 44 1 2 1 2 1 2 qV qV qE d qE d qEd Vqd d qV                    The gain in kinetic energy of the positive ion is independent of d. 21 C x n A 400 200 12.5 B 400 500 5.0 C 650 200 7.7 D 650 500 3.1  / nm

Anglo-Chinese Junior College 2021 H2 Preliminary Exam Paper 1 Guide H2 (9749) Physics JC2 2020 Page 4 of 4 22 A 2 2 2 1 I nevA Iv neA I dne v d       If d increases linearly with position x, dx . 2 1v x When x increases, v decreases at a decreasing rate. 23 C 24 D     22 2 2 2 () BLvI RR BLvF BIL B L R B L vF R B L vP Fv R L is the length of the rod in contact with the rail. 25 B Centripetal force when entering is upwards hence magnetic force is upwards. Using Fleming’s right hand rule, current is in the same direction as the path so it must be positively charged. If direction of magnetic force is upwards, electric force must be downwards so electric field must also be downwards. 26 C Laminating the iron core in a transformer narrows the eddy current paths which reduces the induced e.m.f. and hence the eddy currents. 27 D For a 4-level system, the number of possible transitions is 4 2 6C  28 A Higher p.d.  higher KE  max energy of photon is higher  min is smaller 29 B 30 B