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. in calculating the mass m of air that hits the wall in one second, the speed of the air must be involved: m =12m2 x 33ms-1 x 1.2kgm-3 = 475.2kgs-1. The rate of change of momentum (force) is therefore this expression multiplied by its velocity, 33ms-1, giving an answer of 16000N. Keeping units in a calculation like this will result in an answer with the units of momentum. Missing out the 33m will give incorrect units for force.
 

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. 

53 comments:

  1. Could you do number 27?

    ReplyDelete
    Replies
    1. check question 97 at
      http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-18.html

      Delete
  2. No .36 please? Thank you! :)

    ReplyDelete
  3. Work solution for June 2013 paper 13 esp Q6, Q19 & Q33
    Tq

    ReplyDelete
    Replies
    1. Solution for question 19 is available as solution 171 at
      http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-28.html

      Delete
  4. Replies
    1. Explanations for Qu 38 are now available

      Delete
  5. why did you us 33ms to find the mass? thye didmt say its length way 33.

    ReplyDelete
    Replies
    1. Which question is it? Did you read it correctly because I don't think I would use a value not given in the question

      Delete
    2. they didnt say the length is 33m

      Delete
    3. It's the speed of the wind. maybe I missed this detail:
      {mass per second = (area x speed) x density = (volume per second) x [mass / volume] = mass per second}

      Read the explanations carefully, think and at least try to understand on your own first.

      Delete
  6. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. I'm currently solving the doubts that were posted before yours. I'll try to solve your questions that you asked soon. But I can't promise that Ill be able to solve them all

      Delete
    2. Try to look at the others questions that are already solved in the meantime

      Delete
    3. This comment has been removed by the author.

      Delete
    4. Sorry, but I can't do that. but i'll try to solve some of the questions you already asked. So, check again

      Delete
  7. question 6 please

    ReplyDelete
    Replies
    1. Explanations for question 6 has been added

      Delete
  8. Q33 explanation please?

    ReplyDelete
    Replies
    1. Explanation for this questions has been added

      Delete
  9. Replies
    1. Explanations for Q35 has been included

      Delete
  10. Replies
    1. Solution for Q28 is now available

      Delete
  11. Can I please get help with these?
    w14/p13/ questions 3 and 27
    w14/p12/ questions 10, 21, 23, and 31.
    w12/p11/ question 29

    ReplyDelete
    Replies
    1. some of explained at
      http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-102.html

      Nov 2014 Paper 13 Q3 explained at
      http://physics-ref.blogspot.com/2015/03/physics-9702-doubts-help-page-94.html

      Delete
    2. Nov 2014 P12 Q10 explained at
      http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-103.html

      Delete
  12. Q5 pls pls please!

    ReplyDelete
  13. Could you add Q29 and Q30 plz?

    ReplyDelete
  14. hi can you explain june 2009 paper 1 question 14 and 33 please? :s

    ReplyDelete
    Replies
    1. For Q14, see solution 843 at
      http://physics-ref.blogspot.com/2015/06/physics-9702-doubts-help-page-168.html

      Delete
  15. for q13, explanation on C, how will the mass of a body be changing? and if the mass is changing, isn't the momentum should be changing too? since momentum is the product of mass and velocity.

    ReplyDelete
    Replies
    1. we usually do not consider the mass of the fuel but this actually decreases. so the momentum would change and so will the force, even if the speed is constant.

      Delete

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