A2 Physics | Post your doubts here

[angelicsuccubus]

Check out Mathy's A2 physics notes!

I can't find them.. and I'll attempt the q you just posted..

 

[arlery]

I can't find them.. and I'll attempt the q you just posted..

http://www.xtremepapers.com/community/threads/my-notes-for-biology-and-physics-a2.14550/#post-232270

Alright, thanks!

 

[angelicsuccubus]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_41.pdf
In Q 2 b (iii) How can I get 840 for the work done on gas for R -->P? :S

is it meant to be 840? I tried a bunch of things.. and i get either 880 or 240..

 

[arlery]

is it meant to be 840? I tried a bunch of things.. and i get either 880 or 240..

Same here! I can't get 840 either :S

 

[Anneihtseme]

URGENT HELP, MY EXAM IS COMING IN LESS THAN 7HRS
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w07_qp_4.pdf
any one helps me with the question 5b (ii)
The questions to use the given diagram to determine the initial charge.
Here is what the mark scheme says:

(ii) area is 21.2 cm2 (allow ±0.5 cm2) .......................................................................C2
(allow 1 mark if outside ±0.5 cm2 but within ±1.0 cm2)
1.0 cm2 represents (0.125 × 10-3 × 1.25 =) 156 μC ..............................................C1
charge = 3300 μC .................................................................................................A1(ii) area is 21.2 cm2 (allow ±0.5 cm2) .......................................................................C2
(allow 1 mark if outside ±0.5 cm2 but within ±1.0 cm2)
1.0 cm2 represents (0.125 × 10-3 × 1.25 =) 156 μC ..............................................C1
charge = 3300 μC .................................................................................................A1

Examiner's report

Successful candidates either counted squares or used a series of vertical strips. The conversion of
the area to a charge presented few problems apart from a power-of-ten error. A significant number
of candidates found the area of a single strip near to the origin on the x-axis. Presumably they
thought that this initial strip would represent the initial charge stored in the capacitor.

 

[angelicsuccubus]

Same here! I can't get 840 either :S

what does it say in the markscheme?

 

[arlery]

the ans is - 840 J

 

[angelicsuccubus]

Same here! I can't get 840 either :S

whats that rule ..Q= W + someting.. first law of thermodynamics? thats whats goin on.. 240--600= 840 .. cause they specifically said its a PQRP cycle.

 

[arlery]

whats that rule ..Q= W + someting.. first law of thermodynamics? thats whats goin on.. 240--600= 840 .. cause they specifically said its a PQRP cycle.

but where'd the 600 come from?

 

[angelicsuccubus]

but where'd the 600 come from?

they gave it in the table.. its change in internal energy= heat supplied + work done... and because its a cycle, the last thing uses the values of the first step... P--Q is the same as R--P

 

[arlery]

they gave it in the table.. its change in internal energy= heat supplied + work done... and because its a cycle, the last thing uses the values of the first step... P--Q is the same as R--P

Mmmm ohh alright. Ekh that's an awful lot of thinking. :/

 

[angelicsuccubus]

Mmmm ohh alright. Ekh that's an awful lot of thinking. :/

haha are you kidding me? ... do you even read everyone else's long winded freaky answers? This place and the people here scare the crap outa me with how well they're prepared !

 

[arlery]

haha are you kidding me? ... do you even read everyone else's long winded freaky answers? This place and the people here scare the crap outa me with how well they're prepared !

“Don’t compare yourself with anyone in this world. If you do so, you are insulting yourself.” – Alan Strike
Try not to, your prep seems great as it is to me. What's meant to happen will happen anyway, and everything happens for the best. You've done your part in working for it, do a bit more and sleep with ease leaving everything to God.
Pondering over pointless matters like others' prep will do no good except demotivating you.

 

[angelicsuccubus]

“Don’t compare yourself with anyone in this world. If you do so, you are insulting yourself.” – Alan Strike
Try not to, your prep seems great as it is to me. What's meant to happen will happen anyway, and everything happens for the best. You've done your part in working for it, do a bit more and sleep with ease leaving everything to God.
Pondering over pointless matters like others' prep will do no good except demotivating you.

0.0 philosophical much?
Anyway, what are the formulae for op-amp and shizz? The one's relating Vout and Gain and all that.. ?

 

[angelicsuccubus]

What's going on in 9 b) i ?
http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s11_qp_41.pdf

 

[arlery]

0.0 philosophical much?
Anyway, what are the formulae for op-amp and shizz? The one's relating Vout and Gain and all that.. ?

mmhmm
*Voltage gain = output voltage/input voltage
*V out= A0 ( V+ minus V-)
where A0 is the open loop gain of amplifiar, V+ is the voltage at the non inverting end and V - is the voltage at inverting end.
* For an inverting amplifiar: V out/Vin = -Rf/Rin
*For a non inverting amp: Vout/V in = 1 + Rf/R1

 

[arlery]

What's going on in 9 b) i ?
http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s11_qp_41.pdf

Get the value of R from the graph.

 

[angelicsuccubus]

mmhmm
*Voltage gain = output voltage/input voltage
*V out= A0 ( V+ minus V-)
where A0 is the open loop gain of amplifiar, V+ is the voltage at the non inverting end and V - is the voltage at inverting end.
* For an inverting amplifiar: V out/Vin = -Rf/Rin
*For a non inverting amp: Vout/V in = 1 + Rf/R1

Thank you =]

 

[angelicsuccubus]

Get the value of R from the graph.

sorry I meant B ii

 

[arlery]

Thank you =]

You're welcome.