Saturday, June 28, 2014

9702 June 2012 Paper 12 Worked Solutions | A-Level Physics

  • 9702 June 2012 Paper 12 Worked Solutions | A-Level Physics


Paper 12


1 C                  11 B                21 C                31 C
2 D                  12 D                22 C                32 C
3 D                  13 A                23 C                33 D
4 B                  14 B                24 B                34 B
5 B                  15 D                25 C                35 D
6 A                  16 D                26 D                36 D
7 A                  17 B                27 C                37 D
8 D                  18 D                28 D                38 C
9 A                  19 B                29 C                39 B
10 A                20 D                30 B                40 B






Notes for some specific questions:

3 - Ans: D. {Detailed explanations for this question is available as Solution 1117 at Physics 9702 Doubts | Help Page 240 - http://physics-ref.blogspot.com/2016/07/physics-9702-doubts-help-page-240.html}




4 – Ans: B. {Detailed explanations for this question is available as Solution 287 at Physics 9702 Doubts | Help Page 48 - http://physics-ref.blogspot.com/2015/01/physics-9702-doubts-help-page-48.html}


5 – Ans: B. A in incorrect because the measurements are not precise since the values differ significantly and they (the measurements) are not accurate since none of the values are close to the averaged one. The measurements are not always recorded to degree of precision of measuring device (1st one). Systematic errors cannot be estimated by repeating the experiment with the same equipment.


7 - Ans: A. {Detailed explanations for this question is available as Solution 518 at Physics 9702 Doubts | Help Page 101 - http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-101.html}



8 – Ans: D. consider motion from point of release to M1. At time=0 velocity, u = 0ms-1. So, using the formula s = ut + ½at2, we may write x = 0(t1) + ½at12. Call this equation (1). Now, consider motion from point of release to M2. Again, using the formula s = ut + ½at2, we may write x + h = 0(t2) + ½at22. This is equation (2). Since there is no x in the answers given, we need to eliminate it from our equations. This is done by taking equation (2) – equation (1) such that x + h – x = ½at22 – ½at12. So, a = 2h / (t22 – t12).

9 – Ans: A. Brick is falling, so height decreases with time. [C and D are incorrect] Gradient of the graph gives speed of fall of brick. Due to gravity, there is an acceleration of 9.81ms-2, so speed keeps on increasing until it reaches the ground. So, gradient is not constant. [B is incorrect]


10 - Ans: A. {Detailed explanations for this question is available as Solution 947 at Physics 9702 Doubts | Help Page 195 - http://physics-ref.blogspot.com/2015/09/physics-9702-doubts-help-page-195.html}


11 - Ans: B. {Detailed explanations for this question is available as Solution 513 at Physics 9702 Doubts | Help Page 100 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-100.html}


12 - Ans: D. {Detailed explanations for this question is available as Solution 932 at Physics 9702 Doubts | Help Page 192 - http://physics-ref.blogspot.com/2015/08/physics-9702-doubts-help-page-192.html}


13 – Ans: A. {Detailed explanations for this question is available as Solution 425 at Physics 9702 Doubts | Help Page 80 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-80.html}


14 – Ans: B. {Detailed explanations for this question is available as Solution 974 at Physics 9702 Doubts | Help Page 201 - http://physics-ref.blogspot.com/2015/09/physics-9702-doubts-help-page-201.html}


15 – Ans: D. {Detailed explanations for this question is available as Solution 769 at Physics 9702 Doubts | Help Page 155 - http://physics-ref.blogspot.com/2015/05/physics-9702-doubts-help-page-155.html}


16 - Ans: D. {Detailed explanations for this question is available as Solution 813 at Physics 9702 Doubts | Help Page 163 - http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-163.html}


17 - Ans: B. {Detailed explanations for this question is available as Solution 557 at Physics 9702 Doubts | Help Page 109 - http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-109.html}


20 - Ans: D. {Detailed explanations for this question is available as Solution 1062 at Physics 9702 Doubts | Help Page 223 - http://physics-ref.blogspot.com/2015/11/physics-9702-doubts-help-page-223.html}



22 - Ans: C. {Detailed explanations for this question is available as Solution 332 at Physics 9702 Doubts | Help Page 58 - http://physics-ref.blogspot.com/2015/02/physics-9702-doubts-help-page-58.html}


23 - Ans: C. {Detailed explanations for this question is available as Solution 361 at Physics 9702 Doubts | Help Page 64 - http://physics-ref.blogspot.com/2015/02/physics-9702-doubts-help-page-64.html}


24 - Ans: B. {Detailed explanations for this question is available as Solution 476 at Physics 9702 Doubts | Help Page 92 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-92.html}


25 - Ans: C. {Detailed explanations for this question is available as Solution 363 at Physics 9702 Doubts | Help Page 65 - http://physics-ref.blogspot.com/2015/02/physics-9702-doubts-help-page-65.html}


26 – Ans: D. Should allow for reflection. Total distance = 2(150) = 300m. Speed = 3x108ms-1. So, time = 1x10-6s = 1μs.


27 - Ans: C. {Detailed explanations for this question is available as Solution 640 at Physics 9702 Doubts | Help Page 127 - http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-127.html}



28 - Ans: D. {Detailed explanations for this question is available as Solution 166 at Physics 9702 Doubts | Help Page 28 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-28.html}


29 - Ans: C. {Detailed explanations for this question is available as Solution 366 at Physics 9702 Doubts | Help Page 66 - http://physics-ref.blogspot.com/2015/02/physics-9702-doubts-help-page-66.html}


30 – Ans: B. Amplitude is the maximum displacement from equilibrium position. The first rise at position X corresponds to a maxima, the fall to a minimum corresponds to the zero position and position Y corresponds to a minimum. So, the distance XY (internodal distance) is equal to λ/2. time between X and Y =0.33/330 = 1x10-3s = 1ms.  This corresponds to 2 grids on the cro.
 

31 - Ans: C. {Detailed explanations for this question is available as Solution 678 at Physics 9702 Doubts | Help Page 137 - http://physics-ref.blogspot.com/2015/05/physics-9702-doubts-help-page-137.html}


32 - Ans: C. {Detailed explanations for this question is available as Solution 1114 at Physics 9702 Doubts | Help Page 239 - http://physics-ref.blogspot.com/2016/06/physics-9702-doubts-help-page-239.html}



33 – Ans: D. R=ρL/A.  A is incorrect since the charged particles (ions and electrons) are already present in the wire. B is incorrect because the wire with the smaller diameter, and hence, smaller cross-sectional area resulting in a higher resistance. So, for same current to flow in both of them [I=V/R], a larger potential difference should be applied to the smaller wire, causing the average velocity of the charged particles to be faster in the smaller wire. C incorrect because larger diameter > smaller resistance > smaller pd required > less energy provided to charged particles.



35 - Ans: D. {Detailed explanations for this question is available as Solution 364 at Physics 9702 Doubts | Help Page 65 - http://physics-ref.blogspot.com/2015/02/physics-9702-doubts-help-page-65.html}


36 - Ans: D. {Detailed explanations for this question is available as Solution 426 at Physics 9702 Doubts | Help Page 81 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-81.html}


37 – Ans: D.{Detailed explanations for this question is available as Solution 789 at Physics 9702 Doubts | Help Page 159 - http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-159.html}


38 - Ans: C. {Detailed explanations for this question is available as Solution 182 at Physics 9702 Doubts | Help Page 29 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-29.html}




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