ALL CIE PHYSICS DOUBTS HERE !!!

[astarmathsandphysics]

+/-1.5% +/-2 digits
What does +/- 2 digits mean

[aqws0987]

+/-1.5% applies to the total reading shown on the scale and the +/-2 digits is the uncertainty in the final display figure.

Don't know what it means tho 

[tmisterr]

i have an A2 doubt from the app booklet:
pg 8 at the bottom ''the input impedance of the op-amp....'' and fig. 1.13
i dont get it  

Electrical Impedance, is the total opposition that a circuit presents to alternating current. It is a combination of resistance and capacitive reactance I think, it's quite complex but for A2 physics all you need to is they use impedance to mean resistance. since I=V/R, if an op-amp has a very large input impedance(i.e resistance), the value of current will tend toward zero so essentially the op-amp is not drawing any current from the input

Here read these short notes, they will help with your understanding of Op-amps:
http://www.williamson-labs.com/480_opam.htm

I recommend starting with the paragraph that reads "Anyway, because of the aforementioned...." up to "This high impedance input can be used to great advantage: in sample & hold circuits, peak detectors--you name it. "

the rest is un-important literature in the scope of A2 physics

[aloha32]

Can someone please help me with P5 June 2010 Q2b? I need to know what would be the correct absolute error for this

V (Volts) :  5.0 +/- .2
I (10^-3 Amps) : 15 +/- .2
X  (Ohms)         : 330    (as i calculated to 2 sf)

I found the percentage error for V as 4%. But I don't know what to do for I. Do I keep it as (.2/15 X 100) or (.2/.015 X 100)?

Also, for the value of 1/f why do we have to give 3 sf when all the values given to us are in 2 sf?

Here is the link of the mark scheme :
http://www.freeexampapers.com/get_past_papers.php?l=Past_Papers%2FA+Level%2FPhysics%2FCIE%2F2010+Jun%2F9702_s10_ms_51.pdf

Thank you!

[cs]

I need a bit of help here, i have been dealing with questions like this, i don't get how to determine the direction. Can anyone please enlighten me? Thanks

Nov 2004 paper 4 Q5

I couldn't upload the attachment sorry

[Deadly_king]

Can someone please help me with P5 June 2010 Q2b? I need to know what would be the correct absolute error for this

V (Volts) :  5.0 +/- .2
I (10^-3 Amps) : 15 +/- .2
X  (Ohms)         : 330    (as i calculated to 2 sf)

I found the percentage error for V as 4%. But I don't know what to do for I. Do I keep it as (.2/15 X 100) or (.2/.015 X 100)?

Also, for the value of 1/f why do we have to give 3 sf when all the values given to us are in 2 sf?

Here is the link of the mark scheme :
http://www.freeexampapers.com/get_past_papers.php?l=Past_Papers%2FA+Level%2FPhysics%2FCIE%2F2010+Jun%2F9702_s10_ms_51.pdf

Thank you!

It should be of same units. So in this case where current has been given as I (10^-3 Amps) : 15 +/- .2 the calculations for absolute errors are :

% error for I = (0.2 x 10^-3)/(15 x 10^-3) x 100 = 13%

Usually we are to give answers to the same number of sf or one better. I think that answers with 2 sf should also be accepted.

I think from now on, you can proceed with the rest of the question yourself.

[sarsam]

It have been age since last time I came here. I feel so nostalgic about it.
So I came back with a question in my hand



Time taken for 10 oscillation is given 2.83s with uncertainity 0.01

How to calculate uncertainity of time period in this case?
Do we have to divide the uncertainity of time i.e 0.01 with 10?

[xlane]

may june 2007.....paper 5 ,code 9702......question no. 2.....part b.....hiw do u find the uncertainity of l square......L=6.0 (+_) 0.4.....so wat will be l square ??

[tmisterr]

may june 2007.....paper 5 ,code 9702......question no. 2.....part b.....hiw do u find the uncertainity of l square......L=6.0 (+_) 0.4.....so wat will be l square ??

6²=36

fractional uncertainty in l is 0.4/6. so fractional uncertainty for l² which is l*l it will be 2*(0.4/6)=0.8/6
so the absolute error in l²= (0.8/6)*36=4.8
since absolute error is written on one significant figure, it becomes 5
so L² is 36+-5 cm²
 

[xlane]

x ray explanation from apps of physics please...detailed n wat do we need to knw exactly...if possible reference of past paper question please...

[sabrina]

anyone plz help in wat to study for xrays, MRI,
i dont know anything. plz help

[elemis]

With regards to AS Level Physics what do I need to know about viscous drag ?

[basoom16]

question
two +30 micro columb charges are placed on a straight line 0.4 m apart. A +0.5 micro columb charge is to be moved a distance of 0.10 m along the line from a point midway between the charges. how much work must be done.

can anyone please show me how its done.
thankyou

[elemis]

question
two +30 micro columb charges are placed on a straight line 0.4 m apart. A +0.5 micro columb charge is to be moved a distance of 0.10 m along the line from a point midway between the charges. how much work must be done.

plz answer thnk u

I havent done A2 Physics yet.

[HUSH1994]

MJ 2002 Paper 1 Q26,how do u solve this type of questions?