Author Topic: ALL PHYSICS DOUBTS - POST HERE !!  (Read 238123 times)

Offline haris94

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #780 on: May 11, 2010, 06:27:57 pm »
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(

i hv heard that they do not correct anything done in pencil
but for your sake i hope im wrong
WHAT WE DO IN LIFE ECHOES AN ETERNITY

Offline The Golden Girl =D

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #781 on: May 11, 2010, 09:14:20 pm »
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(

be optimistic and pray  cuz god helps everyone ........ " allah yijeeb da3awat ida3i so id3ei Allah ino Allah yiwaf8ak !! ...... ithi8 fi illah wa allah rah yisa3dak  ;) "
Verily, in the remembrance of Allah do hearts find rest(13:28)

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Offline The Golden Girl =D

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #782 on: May 11, 2010, 09:20:19 pm »
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(

 one of the moderators  whose my friend "nid404" said the followin


I went through a tough time last year when I wrote my french listening paper in pencil...lol..but the paper was good. They were kind enough to let go of my folly, I ended up with an A*    CIE can be good sometimes

" she is soo gonna kill me if she sees me postin this :P , actually she won't  ::) "
Verily, in the remembrance of Allah do hearts find rest(13:28)

Please, Don't forget to Include GG in your Prayers =D

Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #783 on: May 11, 2010, 09:37:46 pm »

Of course not .. shes really sweet .. :)

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #784 on: May 12, 2010, 06:53:26 am »
Of course not .. shes really sweet .. :)

i kno  ::)  lol   :P
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Offline WARRIOR

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #785 on: May 12, 2010, 02:21:20 pm »
Hi

I did paper 6 phyics yestreday and i was wondering... the graph for the heat ..the beaker...everyone drew a cure ..but i drew a best fit...how many marks will i lose? and is a best fit graph wrong Sad i feel depressed really..i should have aced paper 6 Sad now my chanced for an A* has decreased Sad o lord Sad 

By the way  i posted this in the forum of all examinations of 2010..no one answrd :( im  hopin some1 asnwes here thx

bttw  i did first variant
NO secrets to SUCCESS , it is the result of 1.HARD WORK 2.GOOD PREPARATION 3.LEARNING FROM FAILURE
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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #786 on: May 12, 2010, 02:33:20 pm »

check again i replied twice .. ;)

Offline SEL123

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #787 on: May 12, 2010, 04:39:23 pm »
I really messed up paper 6 because I didn't realize there were two more pages
I finished the angles stuff at EXACTLY one hour
Then I guessed for the next two pages the answers, while the papers were being taken.
I'm going to have to do AMAZINGLY in paper 1 and 6 to get an A, because the curve for this year is going to be pretty high...

When they ask for justification USING your results
Do we have to say exactly using numbers???
To repeat what others have said, requires education, to challenge it, requires brains.

Offline SEL123

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #788 on: May 12, 2010, 04:43:49 pm »
May June 2007
Number 10 B
There's a thermistor and a transistor

b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"
To repeat what others have said, requires education, to challenge it, requires brains.

Offline SEL123

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #789 on: May 12, 2010, 05:05:41 pm »
And just out of curiosity..
Does anyone know if there are IGs in Lebanon.?
To repeat what others have said, requires education, to challenge it, requires brains.

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #790 on: May 12, 2010, 05:17:41 pm »
May June 2007
Number 10 B
There's a thermistor and a transistor

b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"

There is a designated thread for these kind of dicussions here :

https://studentforums.biz/index.php/topic,7273.msg200847/boardseen.html#new

Offline J.Darren

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #791 on: May 13, 2010, 07:14:23 pm »
May June 2007
Number 10 B
There's a thermistor and a transistor

b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"
Thermistor.

As the temperature increases, the resistance in the thermistor decreases. It is a definiton, as thermistor is made up of semi-conductors.

The lower part of the circuit gets more share of the resistance, more current can then flow through it, thus switching on the lamp.
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline WARRIOR

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #792 on: May 19, 2010, 10:19:54 am »
NO secrets to SUCCESS , it is the result of 1.HARD WORK 2.GOOD PREPARATION 3.LEARNING FROM FAILURE
But it ain't how hard you hit; it's about how hard you can get hit, and keep moving forward-Balboa

Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #793 on: May 19, 2010, 11:26:09 am »
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_31.pdf

question 10 (c)

why do u calculat power and it says energy

10 a)

i) By using a Step Up Transformer

ii) less energy lost from power lines

b) I = P/V
=  55000/22000
= 2.5 A

c) It says "rate of loss of energy"

amount of heat energy transferred to heat due to the resistance of the wires is directly proportional to the square of the current so I2R

P = I2R
 = 2.52 * 3
= 18.75 W



Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #794 on: May 19, 2010, 11:30:06 am »
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_31.pdf

question 10 (c)

why do u calculat power and it says energy

Energy Transferred = Power * Time

Power = I^2 * R

Energy Transferred = I^2 * R * t

t = 1
I = 2.5
R = 3

18.75J..
or 18.75W per second.
divine intervention!