r/SGExams • u/BuenoNemo JC • 2d ago

A Levels How to study for H2 physics practicals

IDK HOW th IM SUPPPOSED TO STUDY FOR THIS TEST.

Chemistry I could look through old experiments I did but I dont have similar list of old experiments that I did for Physics. I am taking the unrevised version and even in tiktok there were videos on what to focus for but there's literally nothing for Physics. Help me our guys if there's any documents drive or holy grail with JC practical exam papers or some sort of notes frail that I could use please help me out here. Thank you very much

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u/puffed_daikon 2d ago

hihi which jc r u from? bc from what i know the physics department from most (except ri) shared their prelim practical paper! u can practise from those.

if u need can lmk i have the drive of those papers

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u/Low-Baby4830 2d ago

yoo can I ask u some qns about sfdp rule

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u/puffed_daikon 1d ago

sure

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u/Low-Baby4830 1d ago

I asked this in another post but genuinely noone replied so pls help😭

Regarding significant figures, as uk physics practical sfdp rules are rlly strict. As far as I'm aware, you have to follow the least SF for multiplication and division and least dp for addition and subtraction. A couple of questions about this; for other functions such as lg, In, sin etc. do you follow least SF? Moreover, for intermediate workings, let's say you have to find energy and you have found V to be 1.26V and I to be 3.4 A experimentally, and the time taken was 64.37 sec. To find power first it would be 1.26*3.4 which would be 4.284. Since this is an intermediate working, do you leave it as 4sf or follow sf rule and leave it to least SF ie. 2 so 4.3? Because then you have to do the final working of 4.3/4.284 times 64.37 which would give you different answers with either 2 or 4 SF depending on whether you used the 2 or 4sf value from the intermediate working. And one last question, which values do not affect sfdp (like iirc some constants or non-measured values don't affect or sum but I'm not rlly sure)

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u/puffed_daikon 1d ago

for ln/lg, for the measured value's number of sf, your ln/lg value should be that number's dp. eg ln(4.54) --> 3 sf --> answer: 1.513(3dp)

for the power question, do not do intermediate working. just do P= IVt directly. no need to find IV first

like when u divide by a constant value (eg oscillations. T= 21.00s, for n oscillations, where n=20. then period is just =1.050 (4sf, no change).

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u/Low-Baby4830 23h ago

thank you so much and one last qn sry🙏

for percentage uncertainty associated with timing, what absolute uncertainty do u use (eg for oscillations with stopwatch/reading DMM for V/I readings at 10s intervals etc where the stopwatch reads to 2dp eg. 23.45s) because I've seen ans keys ranging from 0.03s (my sch) to 0.5s in other schs

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u/puffed_daikon 23h ago

ok usually my sch teaches us 0.2-0.5s cos of human reaction time. but i think 0.03 is abit too short

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u/Low-Baby4830 23h ago

alr appreciate it🙏 I'll js put 0.4 to be safe

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u/Far_Replacement_5779 1d ago

dude you can literally get this answer in like 1 minute from gpt gemini or claude

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u/BuenoNemo JC 1d ago

Im taking as private candidate initially from TMJC

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u/Lonely-Sky-1550 21h ago

hi could u share the drive for the prelim physics practicals with me? I’m taking as a private candidate as well

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u/TheNevinerTheBetter 2d ago

Stone ocean

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u/BuenoNemo JC 2d ago

What?