ACJC 2023 J2 H2 Physics Prelim P3 MS

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 1 of 11 Qn Suggested MS 1)a) If sphere A is to move in the opposite direction, speed of sphere B will have to be higher than the initial speed of sphere A which will mean that total kinetic energy after collision has increased, which is not possible b)i) + = + + = + =+ 2.5 2.5 2.5 2.5 2.0 2.0 2.5 2.0 2.5 2.0 0 2.5(3.6) 0 2.5 2.0 9 2.5 2.0 m u m v m v vv vv Relative speed of approach = relative speed of separation =− 2.0 2.53.6 vv 2.5 2.5 2.5 9 2.5 2.0(3.6 ) 9 7.2 0.44.5 = + + −== vv v ii) ,2.5 2.5(0.4) 2.5(3.6) 16.00.5 −−= = = =fi ave kg pppFN tt Using N3L, the force on the 2.0 kg crate is also 16.0 N c)i) + = + +i i f f fKE gpe KE gpe WD 221 1 2.0(3.0)(1.5) (3.0)(9.81)(2.0) (3.0) 0 15.0( )2 2 sin30+ = + + v 2 1 3.4 58.9 1.5 60 1.24 − + = + = v v ms ii) The crate will reach the bottom of the slope with a much higher speed The will result in it experiencing a much larger vertical force as it moves from the slope onto the vertical surface, potentially damaging the tomatoes.

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 2 of 11 2 (a) Electric field strength E at a point is defined as the electric force exerted per unit positive charge on a small stationary test charge placed at that point in the electric field. (b)(i) 2 0 9 2 12 2 4 2 2 10 4 0 104 8 85 10 2 . .( . )( ) − − − =  =  QE r  = 4.94 ×104 N C-1 (ii)

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 3 of 11 (c)(i) (ii) Electric field strength is the negative potential gradient Gradient points in the direction of the greatest change of potential which is the (opposite) direction of the electric field. There is no component of the electric field strength (electric force) parallel to the equipotential line as this will cause a change in electric potential

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 4 of 11 3(a) The magnetic flux linkage through a whole coil of N turns is the sum of the magnetic flux through the individual turns (b)(i) As the coil rotates, the area of the coil perpendicular to the field changes sinusoidally causing the magnetic flux linkage to change sinusoidally and a sinusoidal e.m.f. is induced, Since the circuit forms a closed loop, a sinusoial current will now follow (ii) cos( ) sin( )=− =− =ddE NBA t NBA tdt dt    2302 6 2 265 10060 max ( )( . )( ) −= = E NBA = 0.516 V = 0.52 V (iii) (c)(i) 0 0 516 0 365 22 . .= = =rms VVV (ii) 0 25 0 25 0 365 0 09125 . . . . = = =  = ss pp s p s NV NV V V VV 30 09125 9 13 1010 . . −= = = s s VIA R

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 5 of 11 4)a) = =8.0 65 F kx x = 0.123xm b)i) max maxKE PE= = = = =22 max max 11 (65)(0.123) 0.4922KE PE kx J ii) = = = 22 max 11 ( ) 0.4922 ooKE mv m x J  = = 212(1.2)( (0.123)) 0.492 0.855 T Ts iii) iv) v)

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 6 of 11 5(a) A photon is a quantum of electromagnetic radiation whose energy is given by the product of the Planck’s constant and its frequency. (b)(i) 34 9 27 -1 6.63 10 656 10 1.01 10 kg m s hp  − − − = =  = (ii) ( )( ) 8 15 6 3.00 10 9.00 10 2.70 10 m x c t − −  =  =   = xp ≳ h 34 6 28 -1 minimum 6.63 10 2.70 10 2.46 10 kg m s hp x − − −   =  = (c) When isolated gas atoms are in the excited state, electrons occupying the higher energy levels will spontaneously transit from the higher energy levels to lower energy levels. Each transition produces a photon whose energy is equal to the energy difference of the two electron energy levels involved in the transition. Discontinuous/discrete coloured lines are produced on a dark background implying only photons of specific energy/wavelength/frequency is emitted, indicating that the energy levels in an isolated atom are discrete. (d) ( )( ) 34 15 18 18 19 6.63 10 3.19 10 2.115 10 J 2.115 10 eV1.60 10 13.22 eV E hf − − − − = =   = =  = ( ) higher lower higher 13.22 13.22 13.6 0.38 eV EE E −= = + − =− (e)(i) s hc eV =+ (Ii) s 1hcV ee   =−  Plotting sV against 1  , hc e is equal to the gradient. ( ) 6 6 1.80 0.70gradient of graph 3.00 2.10 10 1.222 10 V m− −= − =

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 7 of 11 ( )( ) 6 6 19 8 34 1.222 10 1.222 10 1.60 10 3.00 10 6.52 10 J s hc e h − −− − =  =  =

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 8 of 11 6(a)(i) The light is polarised in the same direction as the filter’s polarising direction / polarised in the vertical direction. (a)(ii) (a)(iii) cos 0.179 = → 65.0 = ( ) 2 00cos 65.0 30 0.67−  =II (b)(i) Light from both slits arrive in phase, it would result in constructive interference; if arrive in  rad out of phase, it would result in destructive interference. This corresponds to maximum voltage for constructive and minimum for destructive. As the train moves, it would detect alternating high and low voltages / interference pattern. Peak decreases due to diffraction. (b)(ii)1. ( ) ( ) 9 3 630 10 5.0 1.5 10 Dx d  − − =  =  32.1 10 mx −= (b)(ii)2. Time between two peaks = 30.01 2 10 s5 −= 3 3 2.1 10 2 10 − − = v 11.05 m s−=v (c)(i) ( ) 9 0.13 5.0 5.0630 10 0.13 b b  − = =  52.4 10 mb −= (c)(ii) Peak voltages will be higher. Width of the central bright fringe will be smaller. (d) Reflected waves and incidence waves interfere. I0 180 360

Anglo-Chinese Junior College 2023 H2 Preliminary Exam Paper 3 MS H2 (9749) Physics JC2 2023 Page 9 of 11 Same frequency, opposite direction