Physics: Post your doubts here!

[Browny]

Would they not cut marks for s.f

 

[MiniSacBall]

But in some mark schemes some answers are to 2 s.f

Would they not cut marks for s.f

Post in only 1 post, why are you posting 2 times.
As i said they won't cut marks unless, it is stated in the question, Most of the time it is in 3 significant figures, so don't worry.
The 2 significant one are like this:
eg: if your answer is like 21.998766737230192
Then 3 significant figures is 22.0. So i guess you are confused in this.
Just write it as 3 significant figures, but if questions says something else, go according to it.

 

[Browny]

Post in only 1 post, why are you posting 2 times.
As i said they won't cut marks unless, it is stated in the question, Most of the time it is in 3 significant figures, so don't worry.
The 2 significant one are like this:
eg: if your answer is like 21.998766737230192
Then 3 significant figures is 22.0. So i guess you are confused in this.
Just write it as 3 significant figures, but if questions says something else, go according to it.

Shall I give you some questions which are clearly given to 2.s.f?

 

[_Ahmad]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_22.pdf

Q2 b
Can anyone please explain the sketch

 

[Browny]

Post in only 1 post, why are you posting 2 times.
As i said they won't cut marks unless, it is stated in the question, Most of the time it is in 3 significant figures, so don't worry.
The 2 significant one are like this:
eg: if your answer is like 21.998766737230192
Then 3 significant figures is 22.0. So i guess you are confused in this.
Just write it as 3 significant figures, but if questions says something else, go according to it.

There is a question where the answer is 4.5333333333.....*10^-3, how many s.f. should we leave that to?

 

[MiniSacBall]

There is a question where the answer is 4.5333333333.....*10^-3, how many s.f. should we leave that to?

Shall I give you some questions which are clearly given to 2.s.f?

Dude just don't worry about significant figures, they won't cut the marks, only if the questions says, that your answer should be in _ significant numbers, then only you have to worry about significant figures.
The answer could be both 4.5*10^-3 or 4.53*10^-3
Both are same

 

[Browny]

How can both be same 1 ans is to 2 s.f. other is to 3.s.f. and the marking scheme gives to 2 s.f.

And why won't they cut marks for s.f., the grading threshold is so low because they do cut for s.f..

 

[Thought blocker]

Thought blocker
we have done this so explain dude!

Q3b) I am not sure, better Suchal Riaz help you
Q5b)
i)
2 = I ( 4 + 0.5 + 2.5 )
I = 0.29A
ii)
R across * J = (0.9/1) * 4 = 3.6 omega
V = IR = 0.29 * 3.6 = 1.03V
iii)
Same as ii) i.e is 1.03 as r do not need any value , We are asked reason too in next question
iv)
P.d. across r is 0 hence r in not needed to be consider

 

[♣♠ Magnanimous ♣♠]

Q3b) I am not sure, better Suchal Riaz help you
Q5b)
i)
2 = I ( 4 + 0.5 + 2.5 )
I = 0.29A
ii)
R across * J = (0.9/1) * 4 = 3.6 omega
V = IR = 0.29 * 3.6 = 1.03V
iii)
Same as ii) i.e is 1.03 as r do not need any value , We are asked reason too in next question
iv)
P.d. across r is 0 hence r in not needed to be consider

great!! I was unsure of what you said
but i was too knowing 5b)

 

[Thought blocker]

great!! I was unsure of what you said
but i was too knowing 5b)

ok...

 

[Browny]

Thought blocker can you help me out in the s.f problem?

 

[Thought blocker]

Thought blocker can you help me out in the s.f problem?

Yeah, I generally keep my answer in 3 s.f, whether they ask ask for s.f or not
And in many of the m.s answers are in 3s.f

 

[Browny]

Yeah, I generally keep my answer in 3 s.f, whether they ask ask for s.f or not
And in many of the m.s answers are in 3s.f

Will the examiners cut marks for our answers s.f. not being the same as m.s s.f.?

And it was 50 50 for me some questions in papers are to 2 others are to 3 sometimes within the same question different parts!!!

 

[Thought blocker]

Will the examiners cut marks for our answers s.f. not being the same as m.s s.f.?

And it was 50 50 for me some questions in papers are to 2 others are to 3 sometimes within the same question different parts!!!

In this case,
Gimme that paper's link I'll tell you what do

 

[omaaaar]

Q3b) I am not sure, better Suchal Riaz help you
Q5b)
i)
2 = I ( 4 + 0.5 + 2.5 )
I = 0.29A
ii)
R across * J = (0.9/1) * 4 = 3.6 omega
V = IR = 0.29 * 3.6 = 1.03V
iii)
Same as ii) i.e is 1.03 as r do not need any value , We are asked reason too in next question
iv)
P.d. across r is 0 hence r in not needed to be consider

Thanks a lot

 

[Snowysangel]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s12_qp_21.pdf
Q3 b complete and
Q5 b complete

Mass will move with the greatest speed at the mean positio so 1 is either .2 or .6
It had greatest elastic potebtial energy when the gravational energy is the least so 2 is 0/0.8
3 is again 0.2/0.6
Are these answers righ?

 

[MiniSacBall]

Yeah, I generally keep my answer in 3 s.f, whether they ask ask for s.f or not
And in many of the m.s answers are in 3s.f

I have been saying this guy the exact same thing for like hours, he is so worried about s.f.

Will the examiners cut marks for our answers s.f. not being the same as m.s s.f.?

And it was 50 50 for me some questions in papers are to 2 others are to 3 sometimes within the same question different parts!!!

So now this is from CIE SALLAYBUS:

Mathematical requirements:
take account of accuracy in numerical work and handle calculations so that significant figures are
neither lost unnecessarily nor carried beyond what is justified.

For Practical Assessment only:
Table of results: calculated quantities
Candidates should be able to:
• calculate other quantities from their raw data
• use the correct number of significant figures for these calculated quantities.
Except where they are produced by addition or subtraction, calculated quantities should be given to
the same number of significant figures (or one more than) the measured quantity of least accuracy.
For example, if values of a potential difference and of a current are measured to 2 and 4 significant
figures respectively, then the corresponding resistance should be given to 2 or 3 significant figures,
but not 1 or 4. The number of significant figures may, if necessary, vary down a column of values for
a calculated quantity.
If you want go check for your self! here: http://papers.xtremepapers.com/CIE/...A and AS Level/Physics (9702)/9702_y14_sy.pdf
Are you ok now. Calm down!

 

[Thought blocker]

I have been saying this guy the exact same thing for like hours, he is so worried about s.f.


So now this is from CIE SALLAYBUS:

Mathematical requirements:
take account of accuracy in numerical work and handle calculations so that significant figures are
neither lost unnecessarily nor carried beyond what is justified.

For Practical Assessment only:
Table of results: calculated quantities
Candidates should be able to:
• calculate other quantities from their raw data
• use the correct number of significant figures for these calculated quantities.
Except where they are produced by addition or subtraction, calculated quantities should be given to
the same number of significant figures (or one more than) the measured quantity of least accuracy.
For example, if values of a potential difference and of a current are measured to 2 and 4 significant
figures respectively, then the corresponding resistance should be given to 2 or 3 significant figures,
but not 1 or 4. The number of significant figures may, if necessary, vary down a column of values for
a calculated quantity.
If you want go check for your self! here: http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_y14_sy.pdf
Are you ok now. Calm down!

Yaar, it's obvious if he can't get satisfactory answer, it's not his fault Now he will see by himself, and will be sure

 

[student1415]

Where is 6V ?

sorry it was 5 V in the marking scheme i didnt get tht

 

[Browny]

Then if the data is to 2.s.f then we must leave the ans to 2.s.f.