A2 Physics | Post your doubts here

[RGBM211]

^Anyone ?

 

[musa Khan]

Can someone please please pleaseee solve these? may you get loads of sawaab

These are some questions where even some of the most brilliant people get confused so i hope this helps everyone out, for the drawing questions, please draw on the diagram and give a brief explanation if possible.

Thank you so much

Q: how to draw a line of lower work function for this graph? i know it's supposed to be on the left and have the same gradient but WHERE do you draw it? how do you figure that out ? :$





Q: do part ii please:



Q: please explain in detail how you make these:

 

[Hussnain]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s07_qp_4.pdf
2(c) Why temperature in Kelvin is not used?
3(b),(d)
4(b). 5(b)(ii). 6(b)(ii), 7(b). 10(a)
Please answer as soon as possible.

 

[hassam]

No, The reason it will lose energy does not depend upon travelling more distance... The reason is because of angle... Light ray, when it exceeds a certain degree of Angle from normal, is reflected.. The reflection is called Total Internal Reflection... if TIR doesnot occur, the light will be refracted and energy will be lost..

well it does DEPEND on distance travelled by the light ray cos energy is lost due to scattering and absorption in the glass......its glass inside ...optic fibre is not hollow

 

[omg]

PLEASEEEEEEEEEEEEEEEEEEEEEE ANYONE ((((((((((((((((((((((((((((((((((((
its the 3rd time im posting!!!!
w07 q1 part b (ii) and s08 q3 part (c)(ii) PLEASE HELP

 

[mr_perfect]

AoA,
Because the input to the inverting input of the amplifier is the p.d across P so we have to take its resistance for comparison (coloured red below)
So using the potential divider method:
Inverting input = (Resistance of P / total resistance of thermistor and P) * 2V
Inverting input = (2000 /2000 + 2100) * 2
Inverting input = 0.97 V
This has to be compared with the constant 1V input to the non-inverting input!
View attachment 6990

can u xplain 2 me whats the fuctin of the +5 and -5 that is above and below the opamp

 

[mr_perfect]

umm so basically we take resistance of P(red one) to compare it with the other 2 resistors? had there been a thermistor in place of one of the two resistors we could have taken the pd across thermistor?

yes.yes.yes.yes

 

[smzimran]

can u xplain 2 me whats the fuctin of the +5 and -5 that is above and below the opamp

AoA.
Read the application booklet for detail.
It is the power supply of the op-amp which supplies power to it.
If output voltage exceeds its value, the op-amp saturates and the output is then equal to this value!

 

[Hammad Siddiqi]

well it does DEPEND on distance travelled by the light ray cos energy is lost due to scattering and absorption in the glass......its glass inside ...optic fibre is not hollow

I got your point but it is still incorrect to suggest that light intensity depends upon distance..
because here we are talking about light... i does not matter if light has to travel some extra kilometers...
but if the core isnt narrow then no matter how small the distance of optic fibre is, it will still lose more energy than a fibre with narrow core and 3 times the length of the other fibre...

 

[Idris]

PLEASEEEEEEEEEEEEEEEEEEEEEE ANYONE ((((((((((((((((((((((((((((((((((((
its the 3rd time im posting!!!!
w07 q1 part b (ii) and s08 q3 part (c)(ii) PLEASE HELP

The q8c2 shows damping so that amplitude should decrease without any change in period, draw with same period but decreasing amplitude.

 

[Executor]

Ok i dont mean to do spam or anything but please go to the following thread and make dua for all of us :
http://www.xtremepapers.com/community/threads/dua-for-all-candidates.14272/

Dont forget to share and Remember every share makes a difference

 

[Rabib_69]

ANYONE HELP ME CALCULATE THE WORK DONE ON GAS FOR P TO R?

 

[Sulayeman]

Kindly help me with the June 99, paper 2, question 3 of Topic 4 dynamics.

The question is about a lamp stand .. In the solution they have divided the length of the arm in half and subtracted 10 [which is the radius of the circular base of the lamp] kindly let me know why the calculation of distance given in the solutions manual is this way

Part b (iii)

1. Perpendicular dist b/w weight of second arm and point P
( 1/2 x 30 ) - 10 = 5 cm

 

[histephenson007]

View attachment 8542ANYONE HELP ME CALCULATE THE WORK DONE ON GAS FOR P TO R?

From P to R, can also be seen as : PR = PQ + QR

The line PQ is the change in volume and QR is the change in pressure.

Then we can just use the formula :
W = P(V)
W = (24*10^5 ) (6*10-4)
= 1440J

Please inform me if the answer is wrong

 

[doc.ahmed]

there is a problem wid dis explanation cos net force shud be the centripetal force.......(cos centripetal force is not a force on its own)it shud be like Fg-N=Fc........so
Fg-Fc=N ......And N=mg where g is the acceleration of free falll........wat do u say

ya over here the net force is beeen reffered to as the answer of diffrence you found out in previous parts

 

[doc.ahmed]

One condition for a satellite to be in geostationary orbit is that the orbit of the
satellite must lie in the plane containing the equator. Explain why this is
necessary?

seriously i need help on this too

 

[umarashraf]

seriously i need help on this too

Earth revolves around its axis... (equator) so naturally a satellite following the earth's passage does not need any extra energy for rotation... and it always have some speed in the direction of its motion....

 

[SkyPilotage]

Can someone please please pleaseee solve these? may you get loads of sawaab

These are some questions where even some of the most brilliant people get confused so i hope this helps everyone out, for the drawing questions, please draw on the diagram and give a brief explanation if possible.

Thank you so much

Q: how to draw a line of lower work function for this graph? i know it's supposed to be on the left and have the same gradient but WHERE do you draw it? how do you figure that out ? :$

View attachment 8428

View attachment 8427

Q: do part ii please:

View attachment 8429

Q: please explain in detail how you make these:

View attachment 8430

View attachment 8431


View attachment 8432

Please upload the question papers i.e which year and question, so that I may upload pictures for you! It will be much easier for me to find the questions

 

[SkyPilotage]

Assalamu alaikum,
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w06_qp_4.pdf
Pls solve Q.6 , part c(2 ) ;
Pls explain why it's V( nought ) used instead of Vr.m.s.?? Thanks

Its asking for a FULLY charged capacitor i.e Vnode which means V maximum .

 

[XPFMember]

Assalamoalaikum wr wb!!
reposting the ones left
JazakAllah khairen for solving the other ones..many duas 4 all....

PAPER 4 doubts...

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Nov 2003

· Q:4 c Can you show, how is the less ripple represented, please.. :s​

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June 2004

· Q:4 c reason for the answer...​

· Q:6 last part..​

· Q:8 iii who said we didn’t use them? :s​

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June 2006

· Q:2 b (ii) how to do?? :s​

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· Q:6 c what do I write for this?

· Q:7 Can you answer the complete question, I couldn’t do this one... ​

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Nov 2006

· Q:3 c what to write? :s​

· Q:6 a (ii) How do the diode works then, normally...isn’t that the way we usually connect? :s​

June 2007

· Q:3 d (i) Why is the answer zero? Just to confirm, is it because E=F/Q and F = ma so E is proportional to a...and hence a will be max. when E is max? is it?​

· Q:4 c (ii) How’ll the diagram be? :s​

· Q:7 b I don’t get why the damping is reduced...i took it as, resistance is increased, more power dissioated, hence more energy losses...so oscillations die off quicker..but it say damping is less..:s confused..​

· Q:7 c (iii) can you give some examples? :s​

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Nov 2007

• Q:1b(i) I don’t understand how to do this..i did see the mark scheme but still I wanna know why to do this..or how to arrive at this..:s
• Q:4 b need explanation + how to draw..?
• Q:4 c (ii)I don’t understand, can someone plz explain me..
• Q:4 d explanation... :s
• Q:5 b (ii) Which area do I determine...

??