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PHYSICS PAPER 2 HELP and NOTES

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everyone please put some notes in here, and add your questions, so that you can get help, the exam's 2 days away so be quick :)
 
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can sum1 explain me how to do question 14b from january 2012 asap

Uhh. I can tell you the way I did it, but it is a bit backwards.

As we know the reading on V1 is 4V, and the resistance is 10 Mega Ohms, or 1 x 10^7 Ohms.

Using V=IR you can find the current, which is 4 x 10^-7 A.

Then, using V=IR again, the second voltage being 2V, the resistance of the parallel combination is 2 /(4 x 10^-7) Which is 5 Mega Ohms.

Then, using the parallel combination of 1/R = 1/R1 + 1/R2 You will say that 1/(5 x 10^6) = 1/R1 + 1/(1 x 10^7)

Thus leading you to R1 = 1 x 10^7 Ohms, or 10 Mega Ohms.

Hope I helped in some way, I don't really know the way they expected you to work through this :p
 
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can sum1 gv me d ans to question 14 a from jan 2012 and Q16b AND q18C from jan 2012 too plz
 
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Uhh. I can tell you the way I did it, but it is a bit backwards.

As we know the reading on V1 is 4V, and the resistance is 10 Mega Ohms, or 1 x 10^7 Ohms.

Using V=IR you can find the current, which is 4 x 10^-7 A.

Then, using V=IR again, the second voltage being 2V, the resistance of the parallel combination is 2 /(4 x 10^-7) Which is 5 Mega Ohms.

Then, using the parallel combination of 1/R = 1/R1 + 1/R2 You will say that 1/(5 x 10^6) = 1/R1 + 1/(1 x 10^7)

Thus leading you to R1 = 1 x 10^7 Ohms, or 10 Mega Ohms.

Hope I helped in some way, I don't really know the way they expected you to work through this :p
thnx a lot..it was a great help :)
 
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^ same thing here , but that's like the BEST physics unit 2 I've ever come across that's why I'm keen to know if there is one for unit 4 and 5 :) ..thanks :)
 
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np, I'll be searching for something similar, and I'll post anything I find here, or perhaps I'll send it directly to you. Don't worry :)
 
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