# 2016 A Level H2 Physics (9646) Paper 1 Suggested Solutions

All solutions here are SUGGESTED. Casey will hold no liability for any errors. Comments are entirely personal opinions.

1. B
2. C
3. B
4. D
5. D
6. C
7. D
8. D
9. B
10. C
11. A
12. D
13. D
14. C
15. C
16. A
17. D
18. A
19. B
20. D
21. Question 21 is a flawed question. When unpolarised light goes through a polarizer, the I is halved while the A is reduced by a factor of root 2. But based on the information Cambridge provides, the answer is C.
22. D
23. D
24. C
25. C
26. B
27. C
28. A
29. B
30. B
31. A
32. C
33. D
34. B
35. B
36. B
37. D
38. C
39. C
40. C

Note to all: Casey will not respond to most of the comments as he is busy. You may contact him by SMS at  +65 9474 5005 if you have a burning question.

Feel free to explain the answers, if you are confident. Many thanks.

• Do Not Call Me

It will be good if the suggested answers is in a table form. Much neater and clearer.

• KS Teng

• Grace tan

• KS Teng

Yup, Casey is working on it.
But expect slight delays as we are overseas already.

• Grace

Ok thank you very much!

• A random guy

shldnt the answer for qn 21 be A as the the last polariser is perpendicular to the first so it does not matter what the 2nd polariser does to intensity

• KS Teng

It would have been if there weren’t the middle one.
– Casey

• Dogdog Dogcat

Sir, mind reviewing question 28 , I think the answer is C as the question wrote resistance decrease when temperature decrease which is not the conventional thermistor. Thank you.

• KS Teng

High temp and high brightness means the R is very small, so the voltmeter reading is small

– Casey

• dude

But that is only for ntc thermistors. The question specified that the resistance of thermistor decreases with temperature, which means as T decreases, R decreases. So R is min when T is low, ans should be C.

• nazurah

• tengks

My students range from 27 – 29, 80% more than 30.

• KX

I found it easy, except 2 or 3 qns that required further thinking. The rest is managable with careful reading

• Keli

Hi! could i have H1 answers for phy:)would really appreciate it!!

• tengks

Hi Sorry but we kinda don’t have the time to produce it!

• zzz

For 28 the qn says resistance of thermistor decreases with temperature so shouldn’t it be C?

• :)

If resistance decrease with temperature, it is the normal thermistor isn’t it? So higher temperature, smaller resistance, potential difference will hence be small.

• Ng Ze Wei

doesn’t resistance decrease with temperature mean when temperature drops, resistance drops correspondingly? It aint the normal thermistor then right?

• Ng Ze Wei

hello moderator i did not realise that i left my name, will it be possible to delete that comment? thank you:)

• KS Teng

High temp and high brightness means the R is very small, so the voltmeter reading is small

– Casey

• lly

Qn 21 is not flawed, answer is I/8, the amplitude is not halved after the first polarizer so the amplitude after 2nd polarizer is given correctly. However intensity is halved for each polarizer passed through.

• lly

Correction: A not reduced by a factor of root 2 for the first polarizer.

• Yanny

Hi, it is not possible to half the intensity without A/ root 2 the amplitude.

• Yanny

AS it will go against the laws of I proportional to A^2

• Yanny

So the ensure malus law is obeyed, we assume I doesnt have any change when first one is passed through as Amplitude no change.

• Peter

Did your students say whether this paper was easier or harder? What do you think the average for this paper is?

• Hude

What’s the national average for mcq every year? :/ i’m worried I can’t even get a C… i only score 27 for this mcq according to your ans

• tengks

My students range from 27 – 29, 80% more than 30.

• W

Why qn 5 is D not B
Why qn 38 is C not A?

• bob

can someone explain qn 38 thx

• Yanny

Ello, that is only true if the polarizer is before it. Meaning, if the 2nd and 3rd polarizer is 90 degrees, then you are right. It is 0. If in this case, because the first and third is seperated by the second, it is no longer 0 as it is only 45 degrees between the second and third.

• K

OMGGGG what’s the usual cut-off mark for an A??

• L

How many marks is required to score A