Author Topic: ALL PHYSICS DOUBTS - POST HERE !!  (Read 199440 times)

Offline jellybeans

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1125 on: May 25, 2010, 12:41:34 pm »
..help ? :)
dont get it :( is it cuz its.. totally internally reflecteeeed? :/
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Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1126 on: May 25, 2010, 12:43:19 pm »
..help ? :)
dont get it :( is it cuz its.. totally internally reflecteeeed? :/

B?
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Offline Moonlyte

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1127 on: May 25, 2010, 12:44:40 pm »
Happened to have just done that paper  ;D
Okay, so let's eliminate the incorrect choices. C and D are IMPOSSIBLE. Why, since we want a CONVECTION current to be set up. so there has a to be a difference in temperatures of the particles, not simply moving them.
So now if we cool it at Y- since it is already at the bottom of the beaker, won't move upwards, so no current, it just stays where it is.
SO now the only plausible solution we have is A, so if we cool the water at X, it'll move downwards due to being denser n here you go- ur very own CONVECTION CURRENT  ;D
Hope I made sense to u

thanks to you and everyone else who answered it! :)

holtadit

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1128 on: May 25, 2010, 12:45:27 pm »
..help ? :)
dont get it :( is it cuz its.. totally internally reflecteeeed? :/

Its B.

The ray travels along the normal and doesnt refract.

Then it hits the slanted edge of the prism and undergoes total internal reflection.

 So its REFLECTED at an angle of 45 degrees downwards where it hits the prism side along the normal and without refracting.

Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1129 on: May 25, 2010, 12:46:47 pm »
B?

yup ..

logic ?? only this one makes sense !! u gotta remember hoe reflection occurs in a a reflecting prism

Offline ambitious94

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1130 on: May 25, 2010, 12:51:25 pm »
Accelerate constantly.

F = ma
1N = ma

1N/m = a

m is constant, thus a is constant.
Ohhh. Thanks 2 u n VIN as well! XD

Offline Moonlyte

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1131 on: May 25, 2010, 12:53:34 pm »
is the marking scheme ever wrong?

holtadit

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1132 on: May 25, 2010, 12:58:07 pm »
is the marking scheme ever wrong?

The MS for those really old papers can be wrong - they were made by some teacher.

For the NEW papers from like 2001 onwards - the MS is ALWAYS CORRECT.

Offline Nobody

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1133 on: May 25, 2010, 12:58:50 pm »
Can somebody upload the physics AQA A unit 2 January 2010 paper and mark scheme? I'm really struggling in general and really need as much practice as possible.

Sorry, but i could't find it anywhere..
But the latest is here..

http://web.aqa.org.uk/qual/newgcses/science/new/physics_materials.php
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Offline Navthep

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1134 on: May 25, 2010, 01:04:16 pm »
Hey guys, i really need help about thermal capacity of an object.
There is one question, June 2006 : P1 : Q16  , the answer is A but i think its B.
Can anyone explain it to me? I have to do the real IG exam tomorrow! (P1)
Thanksss

holtadit

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1135 on: May 25, 2010, 01:05:51 pm »
Hey guys, i really need help about thermal capacity of an object.
There is one question, June 2006 : P1 : Q16  , the answer is A but i think its B.
Can anyone explain it to me? I have to do the real IG exam tomorrow! (P1)
Thanksss

HIGH thermal capcaity = SMALL temp rise.

LOW thermal capacity = LARGE temp rise.


Answer = B

Offline Moonlyte

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1136 on: May 25, 2010, 01:06:44 pm »
The MS for those really old papers can be wrong - they were made by some teacher.

For the NEW papers from like 2001 onwards - the MS is ALWAYS CORRECT.

thanks!

Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1137 on: May 25, 2010, 01:07:09 pm »
The answer is A but Why...Arent the electrons in outer orbits?  ???
Thx
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Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1138 on: May 25, 2010, 01:08:14 pm »
HIGH thermal capcaity = SMALL temp rise.

LOW thermal capacity = LARGE temp rise.


Answer = B

Can u explain..Wat the high/low thermal capactiy actually means..?
Thx
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Offline Navthep

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #1139 on: May 25, 2010, 01:08:50 pm »
HIGH thermal capcaity = SMALL temp rise.

LOW thermal capacity = LARGE temp rise.


Answer = B

Thanks a lot man, so can I just simply see the smallest temp rise to answer this type of question?   :P