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2018-04-18

【PHYS】2018 DSE Paper 1A (MC) suggested answer

以下答案來自網上,謹供參考及討論之用
同學睇答案前請考慮清楚,如果決定睇,不要太在意試卷答案

MC (not available yet)

答案
  1-5:             B*ADAA
  6-10:            CBAAD
  11-15:          BACDC
  16-20:          BDCBD
  21-25:          CACBA
  26-30:          CCDDD
  31-33:          DBA


Explanation
Note: 
Q1 may be cancelled due to lack of discriminatory power as the explanation of the location of silver coating is way out of DSE syllabus. Most candidates will simply blind guess. 


Q30  D but not B:
Indeed the voltage across the branch with xy included is 6V. However, all the pd of the branch will be taken up by the upper half of resistor which is connected to x, and the xy itself, being the remaining part of the branch, should share no pd.

continue...


14 則留言:

  1. 作者已經移除這則留言。

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  2. Q30 could you find another way to explain your answer? The explanation is very confusing

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  3. Q30 someone argues that the answer is B as they say that x,y is not connected. Is that true?

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  4. Q30 must be B not D. Note that when you connect a voltmeter between XY, no current will pass through the voltmeter and X and Y. Current will only flow through the bottom half of the resistor, the voltage across bottom half of resistor is 6V. No current will flow through the top half of the resistor, so the voltage across the top half of the resistor is 0V. Thus, overall Vxy = 0V + 6V = 6V.

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    1. I think so. If zw has a 6V power supply, the voltameter and the power is in parallel. So V(xy) =V(zw) =6V

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  5. If the answer is D, you have just won a Nobel prize

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  6. I think the answer for question 9 should be B (Not 100% sure though), because from what I understand, the period of 0.2s in which the particle changes its direction of motion should be approximately equal to the period for it to decelerate from 0.5 ms-1 to 0ms-1(instantaneous stop).

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    1. Nope. Read the question. It later travels in the same speed in opposite direction. a = [(0.5)-(-0.5)]/0.2

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  7. No6 B? The rod has no weight and the wall is smooth

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    1. the rod is hinged to the wall

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    2. You can try to take moment about the point of the string on rod,then the normal reaction should balance the moment of the load

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  8. Can you post the MC of 2018 HKDSE physics in dse00?

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