Author Topic: ALL PHYSICS DOUBTS - POST HERE !!  (Read 205273 times)

Offline $H00t!N& $t@r

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #135 on: May 05, 2010, 04:42:39 pm »
Can sm1 explain what a thermocouple is and its function? and how much about it do we have to know for the igs
 
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Offline Saladin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #136 on: May 05, 2010, 04:55:04 pm »
This is a temperature measuring device.  It consists of two wires of different metals, such as copper and iron, joined together.  If there is a temperature difference between the two junctions, a current flows.  The current causes a deflection on a galvanometer.  So, for example, if the temperature of one junction is at 0OC and the other used to measure the temperature of an object then, depending on the current that flows, it is possible to work out the temperature of the object.
The thermocouple is very sensitive and can measure temperatures from –250OC to 1500OC.  It is especially useful for measuring the temperature of very small objects and rapidly changing temperatures.


Offline $H00t!N& $t@r

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #137 on: May 05, 2010, 05:57:33 pm »
This is a temperature measuring device.  It consists of two wires of different metals, such as copper and iron, joined together.  If there is a temperature difference between the two junctions, a current flows.  The current causes a deflection on a galvanometer.  So, for example, if the temperature of one junction is at 0OC and the other used to measure the temperature of an object then, depending on the current that flows, it is possible to work out the temperature of the object.
The thermocouple is very sensitive and can measure temperatures from –250OC to 1500OC.  It is especially useful for measuring the temperature of very small objects and rapidly changing temperatures.




Thanks alot! you've been really helpful. I've been trying to figure out how to add rep. cz u really deserve it. Cud u tell me hw to do it.  ;D Thanks again!  May you have a successful future. Ameen
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Offline Saladin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #138 on: May 05, 2010, 06:03:25 pm »

Thanks alot! you've been really helpful. I've been trying to figure out how to add rep. cz u really deserve it. Cud u tell me hw to do it.  ;D Thanks again!  May you have a successful future. Ameen

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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #139 on: May 05, 2010, 07:47:31 pm »


hey in the ms they say  refractive index (n) =  sin i / sin r ...  OR  sin r / sin r

so aren't they two different things??

n can some1 explain me the question too..its june 09 paper 3

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #140 on: May 05, 2010, 07:55:43 pm »
Depends on the medium

if water's n= 1.5, air's n= 1/1.5

Offline Ghost Of Highbury

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #141 on: May 05, 2010, 08:20:12 pm »

hey in the ms they say  refractive index (n) =  sin i / sin r ...  OR  sin r / sin r

so aren't they two different things??

n can some1 explain me the question too..its june 09 paper 3

One quick tip about when to use sin r / sin i and the reverse.

Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.

This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.
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Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #142 on: May 05, 2010, 09:23:12 pm »
One quick tip about when to use sin r / sin i and the reverse.

Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.

This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.

But wat if the R.I is given n we r supposed to find an Angle...Is there a way to know using which form of the equation is correct..?
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Offline haris94

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #143 on: May 05, 2010, 09:33:48 pm »
if thats the case, then just keep in mind that
  • if ray is going from denser to rarer, then angle of refraction will be greater than angle of incidence
  • if ray is going from a rarer to a denser medium, then the angle of incidence is greater than the angle of refraction
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Offline Malak

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #144 on: May 05, 2010, 09:49:43 pm »
Sorry, internet bad, very slow cant upload much.

Is this diagram correct for that question :S

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Offline Snake

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #145 on: May 05, 2010, 09:54:47 pm »
Is this diagram correct for that question :S



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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #146 on: May 06, 2010, 05:58:26 am »
u kno last time i asked how am i supposed to study for paper 6 phy IGCSE ...... and some memebers over here answered ...well i got the answer from my tutor and here it goes :

that this paper is very easy it;s alll abt measuring and precautions ad stuff ..the only thing u gotta do is that u should  do as much past papers as u can before the exam ......

(but for me cuz i forget alot  :-[ i might just make a quick revision on the heat lesson as well as the waves )

gd luck !!
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Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #147 on: May 06, 2010, 09:17:59 am »
One quick tip about when to use sin r / sin i and the reverse.

Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.

This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.


hmmm..Thanks.. :)

Offline Vin

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #148 on: May 06, 2010, 09:20:39 am »
u kno last time i asked how am i supposed to study for paper 6 phy IGCSE ...... and some memebers over here answered ...well i got the answer from my tutor and here it goes :

that this paper is very easy it;s alll abt measuring and precautions ad stuff ..the only thing u gotta do is that u should  do as much past papers as u can before the exam ......

(but for me cuz i forget alot  :-[ i might just make a quick revision on the heat lesson as well as the waves )

gd luck !!

yup physics paper 6 is quite easy..
also they usually ask similar questions..so solvin papers as u said is really a good idea..
guess wat my first ever written paper fo igcse is phy paper 6!!!   :) :)

Offline haris94

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Re: ALL PHYSICS DOUBTS - POST HERE !!
« Reply #149 on: May 06, 2010, 09:36:26 am »
every1 who takes physics will hv their first ig exam on 11th may --- phy p6

good luck all!!
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