Wednesday, July 23, 2014

9702 June 2013 Paper 12 Worked Solutions | A-Level Physics

  • 9702 June 2013 Paper 12 Worked Solutions | A-Level Physics


Paper 12


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



Notes for some specific questions:


1 – Ans: B. Both vectors in A and both scalars in C and D.


2 - Ans: B. {Detailed explanations for this question is available as Solution 520 at Physics 9702 Doubts | Help Page 101 - http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-101.html}


3 – Ans: A. Cannot be C since the 2 forces are not equal, so the angle of the resultant cannot be 45 degrees.


5 - Ans: C. {Detailed explanations for this question is available as Solution 834 at Physics 9702 Doubts | Help Page 166 - http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-166.html}


6 - Ans: B. {Detailed explanations for this question is available as Solution 283 at Physics 9702 Doubts | Help Page 47 - http://physics-ref.blogspot.com/2015/01/physics-9702-doubts-help-page-47.html}



7 – Ans: D. initial speed, u = 50ms-1. Final speed (max), v = 10ms-1. Minimum time for passing between 1 and 2, t = 20s (if time is less than this, it means that speed is too fast, so an emergency brake is then applied). Deceleration, a is uniform, so we can use s = ut + ½at2. a = (v-u)/t = (10-50)/20 = -2ms-2. So, s = ut + ½at2 = 50(20) + ½(-2)(20)2 = 600m.


8 - Ans: B.


9 – Ans: D. 
A strong wind of speed33 m s-1 blows against a wall. The density of the air is1.2 kg m-3. The wall has an area of 12 m2 at right angles to the wind velocity.



11 - Ans: D. {Detailed explanations for this question is available as Solution 829 at Physics 9702 Doubts | Help Page 165 - http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-165.html}



12 – Ans: A. Weight is always downward. Since the vehicle is at rest, only the weight will have a component along the slope that will cause the vehicle to go downwards. So, friction, a force which opposes motion would be in a direction opposite to the component of the weight along the slope such that the vertical component of friction would be in a direction opposite to the weight (upward). The normal reaction will be opposite to the other component of the weight.


13 – Ans: B. A is incorrect. C not correct if mass of the body is changing whereas B is always correct under any circumstances.


14 – Ans: D. {Detailed explanations for this question is available as Solution 451 at Physics 9702 Doubts | Help Page 87 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-87.html}


16 - Ans: B. {Detailed explanations for this question is available as Solution 115 at Physics 9702 Doubts | Help Page 21 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-21.html}


17 - Ans: C. {Detailed explanations for this question is available as Solution 183 at Physics 9702 Doubts | Help Page 30 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-30.html}


18 - Ans: A. {Detailed explanations for this question is available as Solution 131 at Physics 9702 Doubts | Help Page 24 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-24.html}


19 – Ans: C. {Detailed explanations for this question is available as Solution 979 at Physics 9702 Doubts | Help Page 202 - http://physics-ref.blogspot.com/2015/09/physics-9702-doubts-help-page-202.html}


20 – Ans: D. {Detailed explanations for this question is available as Solution 1080 at Physics 9702 Doubts | Help Page 228 - http://physics-ref.blogspot.com/2015/12/physics-9702-doubts-help-page-228.html}


23 – Ans: B. {Detailed explanations for this question is available as Solution 165 at Physics 9702 Doubts | Help Page 28 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-28.html}


24 – Ans: D. Taking wavelength of violet light to be 4x10-7m gives the frequency to be 7.5x1014Hz or 1015 when rounded to the nearest power of 10.
 

25 - Ans: D. {Detailed explanations for this question is available as Solution 179 at Physics 9702 Doubts | Help Page 29 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-29.html}


27 - Ans: C. {Detailed explanations for this question is available as Solution 97 at Physics 9702 Doubts | Help Page 18 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-18.html}


28 - Ans: B. {Detailed explanations for this question is available as Solution 490 at Physics 9702 Doubts | Help Page 95 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-95.html}


29 - Ans: C. {Detailed explanations for this question is available as Solution 840 at Physics 9702 Doubts | Help Page 167 - http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-167.html}


30 - Ans: D. {Detailed explanations for this question is available as Solution 1124 at Physics 9702 Doubts | Help Page 243 - http://physics-ref.blogspot.com/2016/10/physics-9702-doubts-help-page-243.html}



32 – Ans: C. Resistance of a copper wire = ρL/A = (1.7x10-8)x2000 / (π(0.5x0.51x10-3)2)  = 166Ω. Since wires are parallel (similar to resistors in parallel), Resistance of cable = (12(1/166))-1 = 14 Ω.


33 - Ans: A. {Detailed explanations for this question is available as Solution 421 at Physics 9702 Doubts | Help Page 79 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-79.html}


35 - Ans: D. {Detailed explanations for this question is available as Solution 423 at Physics 9702 Doubts | Help Page 80 - http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-80.html}


36 - Ans: D. {Detailed explanations for this question is available as Solution 121 at Physics 9702 Doubts | Help Page 22 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-22.html}


38 - Ans: C. {Detailed explanations for this question is available as Solution 181 at Physics 9702 Doubts | Help Page 29 - http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-29.html}


39 – Ans: B. Roughly the alpha particle has a mass of 4u, so 4 x 1.66x10-27kg. This gives 6.6x10-27kg or 10-26 when rounded up.





Explanations have been provided for questions that were found to be more difficult. If you are having other doubts that have not been explained here, you may ask your questions through comments. 

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