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The Ultimate AS Physics Thread

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WannaGoodGrade said:
Also Yes i wanna know the June 09 V1 Q1 b ... Calculating uncertainty by the % method as given in mark scheme

This question is pretty easy.
Hope I've helped you.
 
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Hateexams93 said:
why the brightness decreases when the wavelenght increases ?????????????????????????????

v= Frequency * Wavelenght >> Therefore .. Wavelenght = v/f , So If Wavelength INCREASES Frequency DECREASES.

Now .. Intensity Is Directly Proportional To f^2 >> So If " f " DECREASES The Intensity Will, Generally Speaking Will DECREASE And Likewise BRIGHTNESS will DECREASE :)
 
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maybeitwasnoone said:
WannaGoodGrade said:
Also Yes i wanna know the June 09 V1 Q1 b ... Calculating uncertainty by the % method as given in mark scheme

This question is pretty easy.
Hope I've helped you.
.
...ur final anser is wrong....its wrtitten in ER that final uncertainity must be rounded of to 1 s.f and the ans vale then given musst be consistent with no. of d.ps in absolute error
 
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beststriker said:
Please Anyone help in Nov07/02, q5 a) part. How we can show the phase difference between two waves that is 60 deg...????



One wavelength of a wave consists of 360 degrees. So 60 /360 = 1/6 th of wavelength. So divide the given wave into 6 equal parts and draw the new wave from one part ahead of the old wave.


For the amplitude we have intensity directly proportional to (amplitude)^2. First wave's amplitude is 10 squares.

We have, I = kA^2 therefore k = I / (A^2) so k = (1 / 100)I = 0.01I.


Put this in the equation for the new wave:


0.5I = 0.01I x (A^2)

so new A = (50 ^ 0.5) = approx. 7 squares.

Here's an image for the new wave:
 

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@Mueez:

Calculate the effective resistance of the circuit.
Use power = voltage^2/resistance
 
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Lets revive this forum

A: There isn't any question above

Q:Could anyone please explain the whole point of vector triangles??
they seem simple yet I feel like I'm missing something

for e.g. this question
 

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sniper7137 said:
beststriker said:
Please Anyone help in Nov07/02, q5 a) part. How we can show the phase difference between two waves that is 60 deg...????



One wavelength of a wave consists of 360 degrees. So 60 /360 = 1/6 th of wavelength. So divide the given wave into 6 equal parts and draw the new wave from one part ahead of the old wave.


For the amplitude we have intensity directly proportional to (amplitude)^2. First wave's amplitude is 10 squares.

We have, I = kA^2 therefore k = I / (A^2) so k = (1 / 100)I = 0.01I.


Put this in the equation for the new wave:

why is the other wave wrong, i mean it too does give a phase diff of 60 degree rite. Im sorry im confused, can u pls help me out....



0.5I = 0.01I x (A^2)

so new A = (50 ^ 0.5) = approx. 7 squares.

Here's an image for the new wave:
 
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u find the resultant amplitude
3-2 = 1
then I=kA^2
u already hav k from part c (i)...k=1/9
so ur resultant intensity will be I = 1i/9 (1)^2 = 1i/9
 
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7bii
volatage in the thermistor 6-3.6= 2.4V
current in 2000Ω resistor = 3.6/2000 = 0.0018A
current in 5000Ω resistor = 2.4/5000 = 0.00048A
kirchoff's first law states that the current going into the point is equal to the curent leaving out of that point
so, the current in the thermistor is 0.00048 - 0.0018 = 0.00132A
R=V/I
V is 2.4V (as the voltage is the same in parellel connection)
I is 0.00132A
so R will be 1818.2Ω
 
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Hey guys, need help ASAP.
1st question: May 05, Q 5b(iii)- I dont understand the answer in ms.
2nd question: Oct 07, Q 4(c)-please explain the method, no clue about it.

THX
 
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libra94 said:
u find the resultant amplitude
3-2 = 1
then I=kA^2
u already hav k from part c (i)...k=1/9
so ur resultant intensity will be I = 1i/9 (1)^2 = 1i/9


can u also xplain part c (i)..then it'll be more clear to me..cz i used a different method!!
 
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histephenson007 said:
Lets revive this forum

A: There isn't any question above

Q:Could anyone please explain the whole point of vector triangles??
they seem simple yet I feel like I'm missing something

for e.g. this question

Here you go:

and if the triangle is not a right angled triangle, then use the cosine rule.
 

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libra94 said:
7bii
volatage in the thermistor 6-3.6= 2.4V
current in 2000Ω resistor = 3.6/2000 = 0.0018A
current in 5000Ω resistor = 2.4/5000 = 0.00048A
kirchoff's first law states that the current going into the point is equal to the curent leaving out of that point
so, the current in the thermistor is 0.00048 - 0.0018 = 0.00132A
R=V/I
V is 2.4V (as the voltage is the same in parellel connection)
I is 0.00132A
so R will be 1818.2Ω





@libra 94: i didnt understand da kirchoffs law method... Although i know this method but i cant understand how u applied it here here to get da resultant current... Plz explain it to me ... Thnx.. :)
 
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