Physics P5 in 5 minutes !!!

[Soldier313]

Can someone post how to draw diagrams for the first question form 2007 to 2012 please? It will be really kind of you.

you'll find quite a few here:
https://www.xtremepapers.com/community/threads/solved-physics-paper-5.27095/
If you can't let me know, i'll re-upload them.

 

[perky1]

here's a revision note for 9702 physics paper
Question 1:
first be able to reduce the equation in the simplest form ..i.e y=mX=c ..and recognize the gradient
calculate the data in 3 s.f(generally done) or to one s.f more or equal to the s.f of the raw data
in case of logarithmic calculations, the number of d.p is the number of s.f ..hence for a raw data of 3 s.f the log should be calculated to 3 or 4 d.p
to calculate absolute uncertainty the most accepted method is to calculate the maximum difference and divide by 2 ..sf of uncertainty is usually ignored in the mark scheme but stick to 1 or 2 s.f
plot all the six points,a small encircled dot is acceptable use sharp pencil to plot , and draw the error bars. all to nearest half square on the grid.
(u can also analyze from the graph as how much s.f to use..as the graphs interval's points's tenth division place is to be plotted )
the gradient should be calculated by drawing a triangle and mentioning the points of the vertices in the best-fit line ..the hypotenuse should be greater than halt the length of the best-fit line.
working should be shown clearly
and the worst-fit line is drawn by joining the top of the topmost point's error bar and the bottom of the bottommost error bar..and the line should touch every error bar.
both line should be clearly LABELLED ,and the gradient of worst-fit is calculated in similar way to best-fit ..calculate it on the blank page at the end..and just show the gradient value in working area while calculating the uncertainty in gradient..
the error in gradient is gradient of best fit - gradient of worst fit ,or 1/2 * (steepest line's gradient - shallowest line's gradient)
all calculation to 3 s.f
and for calculations , which is usually related to the calculated gradient, take care of units, power of tens and to calculate the percentage uncertainty work out the value with the gradient and again with the error+the gradient and work out the difference which is the absolute uncertainty , hence calculate the percentage uncertainty .(working is only credited here and calculations are not checked)
Question 2:
state the basic statement, it is awarded 1 mark..such as change pressure and measure power..and repeat(o/n 05)
Draw a diagram with all the equipment you might use during the experimentation of this plan..a basic, well labelled diagram could score many marks; even if the explanation is weak.
identify the control variable
make sure you know the working of some equipments as:
collimator,sonometer, strobe, bourdon gauge, joule meter,thermometers,light-spot galvanometer needle valve, vacuum grease , lightgate, smart pulley ,balance,newton meter,ticker tape data-loggers , optical bench, set squares etc.. don't panic of you don't but u should know what equipment to use to measure something.
make sure u understand the question and collect all the method marks by suggesting means of measuring the quantities u might measure during the experiment.
there are 5 method marks to be scored.
now beware of safety measures. like earmuffs eardrums, goggles , safety screens . sand bucket for falling masses..etc
now be able to point some additional details they are worth 4 marks.
these can also be awarded on a detailed diagram..
suggest the possible ranges of devices, suggest some ways of sophisticating the experiment..but donot make vague references and do not forget why are u performing this experiment .
Best of luck . :Yahoo!: bineetojha

wt was your varient ?

 

[kalpaveen]

yeah, what he said, in this case u dont need to find fractional error because percentages are already fractional errors converted into percentages

i didnt get it......could u plz explain it a bit more....and also wt if L=54.5+/-0.5 ...hw to find the absolute uncerainity of 1/L???

 

[fb.junks]

i didnt get it......could u plz explain it a bit more....and also wt if L=54.5+/-0.5 ...hw to find the absolute uncerainity of 1/L???

uncertainty of 1/L=(.5/54.5) x(1/54.5)=.0002

 

[FRENZYAMU]

i didnt get it......could u plz explain it a bit more....and also wt if L=54.5+/-0.5 ...hw to find the absolute uncerainity of 1/L???

absolute uncertainity :
0.5/54.5 <-----fractional error, now multiply this with ure value that u want to find out , which in this case is 1/L so
(0.5/54.5)x(1/54.5) <----ure absolute uncertainity

when u r given an error like 20 +/- 5%,,,,since the absolute error is in form of a percentage that means ure fractional error will just be 5/100 <-----0.05 and not 0.05/20 which u usually do when an error like 20 +/- 0.05 is given, thats it, simple ?

 

[FRENZYAMU]

i didnt get it......could u plz explain it a bit more....and also wt if L=54.5+/-0.5 ...hw to find the absolute uncerainity of 1/L???

hey i did this q, its 2012 May/ June,,,,,were u taking inverse of 54.5 x 10^-2 ???or just 54.5, cuz make sure u do, but off course u wud've done it by now

 

[Haris Sal11]

"to calculate absolute uncertainty the most accepted method is to calculate the maximum difference and divide by 2 ..sf of uncertainty is usually ignored in the mark scheme but stick to 1 or 2 s.f"

Calculate max difference and divide by two? Could you explain it a bit more?

 

[bineetojha]

I am really sorry guys, i wrote this 2 years ago when i was appearing for my A-levels. I am now a philosophy major and i don't have fresh memory of any Physics topics. Best of luck to everyone.

 

[gary221]

"to calculate absolute uncertainty the most accepted method is to calculate the maximum difference and divide by 2 ..sf of uncertainty is usually ignored in the mark scheme but stick to 1 or 2 s.f"

Calculate max difference and divide by two? Could you explain it a bit more?

i think he means this:
1st add the uncertainty to the given value = A + a = X
then subtract the uncertainty from the given value = A - a = Y
then subtract the two and and divide by 2 -----> (X -Y)/2

Hope i helped!
All credit to Nibz

 

[Arooba Mahboob]

If you have to square the value, you must add the fractional or percentage uncertainties to get the final uncertainty.
e.g if x=2.1 +/- 0.1
for the answer: x^2=2.1^2=4.41
fractional error = 2 x (0.1/2.1)
absolute error= fractional error x 4.41 = 0.42

final answer : x^2 = 4.41 +/- 0.42 units

Cambridge accepts the above answer, it also accepts if you give the error to one decimal place : 4.4 +/- 0.4. So that's upto you.

My pleasure! Feel free to ask if you have other problems. All the best for exams

Hey! what if it is x^3?? then how will we calculate absolute uncertainties??

 

[fb.junks]

Hey! what if it is x^3?? then how will we calculate absolute uncertainties??

Instead of multiplying 2 u multiply by 3 to get fractional error

 

[afoo.666]

M/J/09 whats the gradient?

 

[1357913579]

Oh and could you please help me with another thing?
How do I find the absolute uncertainties in the table?
And can you please also help me in Q2d in this paper: http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_5.pdf

can anyone please solve the 2d uncertainity(eror) part here pleaseee.

 

[Tammy Hin]

you'll find quite a few here:
https://www.xtremepapers.com/community/threads/solved-physics-paper-5.27095/
If you can't let me know, i'll re-upload them.

Thnx a lot!!!
Do you have the diagrams for other years that were not mentioned by people

 

[Arooba Mahboob]

Instead of multiplying 2 u multiply by 3 to get fractional error

ok. Thank you

 

[Soldier313]

Thnx a lot!!!
Do you have the diagrams for other years that were not mentioned by people

You're welcome.
No, i'm afraid i don't....if you do comw across something, please do share in the thread. Thanx

 

[Manish Lakshman]

here's a revision note for 9702 physics paper
Question 1:
first be able to reduce the equation in the simplest form ..i.e y=mX=c ..and recognize the gradient
calculate the data in 3 s.f(generally done) or to one s.f more or equal to the s.f of the raw data
in case of logarithmic calculations, the number of d.p is the number of s.f ..hence for a raw data of 3 s.f the log should be calculated to 3 or 4 d.p
to calculate absolute uncertainty the most accepted method is to calculate the maximum difference and divide by 2 ..sf of uncertainty is usually ignored in the mark scheme but stick to 1 or 2 s.f
plot all the six points,a small encircled dot is acceptable use sharp pencil to plot , and draw the error bars. all to nearest half square on the grid.
(u can also analyze from the graph as how much s.f to use..as the graphs interval's points's tenth division place is to be plotted )
the gradient should be calculated by drawing a triangle and mentioning the points of the vertices in the best-fit line ..the hypotenuse should be greater than halt the length of the best-fit line.
working should be shown clearly
and the worst-fit line is drawn by joining the top of the topmost point's error bar and the bottom of the bottommost error bar..and the line should touch every error bar.
both line should be clearly LABELLED ,and the gradient of worst-fit is calculated in similar way to best-fit ..calculate it on the blank page at the end..and just show the gradient value in working area while calculating the uncertainty in gradient..
the error in gradient is gradient of best fit - gradient of worst fit ,or 1/2 * (steepest line's gradient - shallowest line's gradient)
all calculation to 3 s.f
and for calculations , which is usually related to the calculated gradient, take care of units, power of tens and to calculate the percentage uncertainty work out the value with the gradient and again with the error+the gradient and work out the difference which is the absolute uncertainty , hence calculate the percentage uncertainty .(working is only credited here and calculations are not checked)
Question 2:
state the basic statement, it is awarded 1 mark..such as change pressure and measure power..and repeat(o/n 05)
Draw a diagram with all the equipment you might use during the experimentation of this plan..a basic, well labelled diagram could score many marks; even if the explanation is weak.
identify the control variable
make sure you know the working of some equipments as:
collimator,sonometer, strobe, bourdon gauge, joule meter,thermometers,light-spot galvanometer needle valve, vacuum grease , lightgate, smart pulley ,balance,newton meter,ticker tape data-loggers , optical bench, set squares etc.. don't panic of you don't but u should know what equipment to use to measure something.
make sure u understand the question and collect all the method marks by suggesting means of measuring the quantities u might measure during the experiment.
there are 5 method marks to be scored.
now beware of safety measures. like earmuffs eardrums, goggles , safety screens . sand bucket for falling masses..etc
now be able to point some additional details they are worth 4 marks.
these can also be awarded on a detailed diagram..
suggest the possible ranges of devices, suggest some ways of sophisticating the experiment..but donot make vague references and do not forget why are u performing this experiment .
Best of luck . :Yahoo!: bineetojha

Hi, do we have to take take of units in question 2 if its in log. Like log(Y/mm) against log(I/10^-2 A) If so how will we convert? Thanks

 

[fb.junks]

For this paper- http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w12_qp_51.pdf

I will quote the examiners report:


So we do not leave the fourth point to be an outlier? Can someone please cross check with their graphs and tell me what you have done? What do the examiners mean by "balancing out the points" ? That we make sure all the points are close to the line?

It is a general thing for the best fit that u try that the most points are on the line and if there are some points not on the line.These points should be balanced to max to 2:1 above or below line which means if two points are above line one should be below the line.Although 1:1 is better.

 

[Zari]

Asalamualikum can anyone help me i just want to ask do we calculate the upper and the lower limits separately or we just calculate the over all uncertainty ?

 

[fb.junks]

Asalamualikum can anyone help me i just want to ask do we calculate the upper and the lower limits separately or we just calculate the over all uncertainty ?

Uncertainty is calculate overall not separate lower or upper limit