Edexcel Physics Unit 2 "Physics at work" June 2013

Jan 2012, q7. The answer is A but I don't get why! Thanks in advance

Someone explained this a few pages ago. Have a lil search.

That's in A2.


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Anyone know how I would work out the reading on the voltmeter?

Coool

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I got a little confused by this question when I did this paper too :/
It was explained to me like this: Basically assuming P.d stays constant and that V=IR you know that the general shape must have a -ve gradient because as I increases, R must decrease (so that V stays the same). The fact that it's a curve and not a straight line is to do with the fact that the current causes the resistor to heat up (I think, so the 'kept at constant temp' thing must be referring to the external conditions only) and given that increased temperature causes resistance to increase (in metals/decrease in other semiconductors), the resistance/current relationship wouldn't be linear. Quite a misleading question in my opinion!

P.d across branches in parallel with the power supply are always equal to the voltage across the power supply I think. So the answer would just be 15v?

Im sorry to say but I think that explanation is plain nonsense.

V=IR
I=V/R
v is constant so I=k/R

Now wont a AS student feel ashamed when they do not know how to sketch a y=k/x
curve???????
Weren't we supposed to learn the curve shape in GCSE itself???

i gave up on physics in jan! so i have to try and teach myself this unit in a couple of days! i wont start the revision till after my exam tomorrow! if anyone can give me some tips and handy ways of remember key terms and equations i would be very grateful!

Alright chill out... just a messy way of explaining it I guess. Sorry! Just how it was explained by my teacher... cheers

Im sorry to say but I think that explanation is plain nonsense.

V=IR
I=V/R
v is constant so I=k/R

Now wont a AS student feel ashamed when they do not know how to sketch a y=k/x
curve???????
Weren't we supposed to learn the curve shape in GCSE itself???

The exam stress has gone to his mind, he's going crazy.

The exam stress has gone to his mind, he's going crazy.

I just have a feeling that the grade boundaries for this series is going to be really high ... we have got some really bright candidates here :P
So the best way to revise is to do all the past papers and all the extra exam questions I can find,eh?

Legend, did you find the answer to your question? I'm also interested .

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I just have a feeling that the grade boundaries for this series is going to be really high ... we have got some really bright candidates here :P
So the best way to revise is to do all the past papers and all the extra exam questions I can find,eh?

anyone know how i would work out the reading on the voltmeter?