OCR PHYSICS B G492~ 9rd June 2014~ AS Physics

Original post by emfp21

My teacher said half a sub division, another one said a whole sub division :/
Anyone???

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To be honest, I'm not really sure how you could get such an uncertainty unless there were issues when reading the measurements (vision problems) but that isn't really relevant. I'd also think that the uncertainty would be the thickness of the trace because ultimately that value will effect your readings. I'm not entirely sure though, I could be wrong.

Reply 42

alicerose2

Original post by Mutleybm1996

Do you have the links? :smile:

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Sorry I was on mobile before so I couldn't put the links in

https://www.youtube.com/user/diggitydev

and

https://www.youtube.com/user/DrPhysicsA

http://www.examsolutions.net/
( super helpful for the mechanics side of things calculations and stuff)

hope this helps it has been a lifesaver for me :smile:

Reply 43

emfp21

We just had some questions, one was estimate the uncertainty in time/voltage measurements, hence estimate uncertainty in the frequency calculations

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Reply 44

bonzo123

Original post by alicerose2

hope this helps it has been a lifesaver for me :smile:

did you make many notes?, I make them but dont understand them :L

videos are the way forward

Reply 45

shloke123

Guys, click on the link below and scroll to the bottom, there are questions and answers for predicted section C questions :smile:

Reply 46

MasterOfTheSwag

Original post by shloke123

Guys, click on the link below and scroll to the bottom, there are questions and answers for predicted section C questions :smile:

Where is the link? You tease :frown:

Reply 47

OP

Any last advice?

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Reply 48

MasterOfTheSwag

By the way, does the answer always have to be the exact numerical answer given in the mark scheme?
Can your answer be very close but only different as you used different significant figures?
I'm doing the June 2009 paper, question 9.a) iv) and I cannot get the answer that they want. They want 0.054 W and I'm not getting answers that round to this exact number.

http://www.ocr.org.uk/Images/59857-question-paper-unit-g492-understanding-processes-experimentation-and-data-handling.pdf

Reply 49

LimbuRonit

Does anyone know how to do this?

1.

L= 110.0 ±0.1 cm, T=2.10±0.5 sec (where the uncertainty is due to the reaction time)

Based on these measurements, what is the value of g and what is the maximum value the of the uncertainty in g?

Reply 50

theoaze

Does anyone else think that the number of significant figures required by the mark scheme is quite inconsistent? It ranges from 2 s.f. to even 4 s.f. Does the number of s.f. depend on context or is there a set number we should round to?

Reply 51

Hicko

8

Original post by Mutleybm1996

Any last advice?

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just try not to cry

Reply 52

Carla Huynh

Original post by LimbuRonit

Does anyone know how to do this?

1.

L= 110.0 ±0.1 cm, T=2.10±0.5 sec (where the uncertainty is due to the reaction time)

Based on these measurements, what is the value of g and what is the maximum value the of the uncertainty in g?

Rearrange the equation given in the stimulus to get g=(4pi^2L)/T. Plug in L and T to get g. The max uncertainty will be when the largest L by the smallest T so plug in 110.1 for L and 1.6 for T. The difference between them is the uncertainty.

*edit: should be divided by T^2 in equation and L is in cm so remember to divide by 100 :smile:

does that help?

Reply 53

Carla Huynh

Original post by theoaze

Does anyone else think that the number of significant figures required by the mark scheme is quite inconsistent? It ranges from 2 s.f. to even 4 s.f. Does the number of s.f. depend on context or is there a set number we should round to?

It depends on the context to a certain extent but as a general rule I'd say 2sf is most commonly I'm the ms. However, it does say that any sensible number of sf is acceptable which depends on the question

Reply 54

Hicko

8

Does anyone have any useful material for section c? I'm really worried about this section...

Reply 55

OP

Predictions on content?

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Reply 56

LimbuRonit

Original post by Carla Huynh

Rearrange the equation given in the stimulus to get g=(4pi^2L)/T. Plug in L and T to get g. The max uncertainty will be when the largest L by the smallest T so plug in 110.1 for L and 1.6 for T. The difference between them is the uncertainty.

*edit: should be divided by T^2 in equation and L is in cm so remember to divide by 100 :smile:

does that help?

I thought the formula for is ....g=4pi^2m (m=gradient)
???

Reply 57

OP

Original post by LimbuRonit

I thought the formula for is ....g=4pi^2m (m=gradient)
???

4pi^2 / m

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Reply 58

alicerose2

Original post by bonzo123

did you make many notes?, I make them but dont understand them :L

videos are the way forward

I made notes in class but i haven't even looked at them they are so shocking! do you have the revision guide? That is pretty handy at explaining things too as long as you don't mind the shock of HELL WE HAVE NOT COVERED THIS IN CLASS I AM BUMMED. ( I am getting this a lot and end up frantically goggling) :frown:

Reply 59

OP