Author Topic: ALL CIE PHYSICS DOUBTS HERE !!!  (Read 151914 times)

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #630 on: May 19, 2011, 05:08:25 pm »
5 (a) Wave Sources which maintain a constant phase relationship are described as coherent sources.

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #631 on: May 19, 2011, 05:10:29 pm »
5 (b) (lambda*D) / a
use this formula 

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #632 on: May 19, 2011, 05:14:18 pm »
5 (c) There would be no complete destructive interference after the slit so the dark fringes will appear light .

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #633 on: May 19, 2011, 05:27:28 pm »
5 (b) (lambda*D) / a
use this formula 

no, your not meant to use that for this question.. its quite confusing actually...

what I have done so far is as follows:

path difference between S1 and S2 = 28 cm

 v = f x (lambda)

S1   330/1000 = 33 cm
S2   330/4000 = 8.25 cm

after this I tried using  (n + 1/2)(lambda)  but I'm getting a wrong answer  :-\
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #634 on: May 19, 2011, 05:58:28 pm »
wavelength of red light is between 620 to 750 so take any from it
suppose take 650nm so change it to meters so that will be= 650*10-9
D is = 2.4
a is 0.86 mm change it to meters so that will be = 8.6*10-4

so substitute the values

((650*10-9)*2.4)/(8.6*10-4)
change the answer to mm

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #635 on: May 19, 2011, 05:59:35 pm »
wavelength of red light is between 620 to 750 so take any from it
suppose take 650nm so change it to meters so that will be= 650*10-9
D is = 2.4
a is 0.86 mm change it to meters so that will be = 8.6*10-4

so substitute the values

((650*10-9)*2.4)/(8.6*10-4)
change the answer to mm

hey I asked about variant 1  :D
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #636 on: May 19, 2011, 06:00:45 pm »
no, your not meant to use that for this question.. its quite confusing actually...

what I have done so far is as follows:

path difference between S1 and S2 = 28 cm

 v = f x (lambda)

S1   330/1000 = 33 cm
S2   330/4000 = 8.25 cm

after this I tried using  (n + 1/2)(lambda)  but I'm getting a wrong answer  :-\
Ok what you did using v=f*lambda is that you found the range of possibilities of lambda...
To find out about all the wavelenghts remember tht for destructive interference the phase difference or path difference should be equal to 1/2 lamda or 3/2 lambda or 5/2 lamda and soo onn. So you just find the lambda by 28x2 or 28x2/3 or 28x2/5 etc... and then count ho wmany wavelelgnths you have in the range.....

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #637 on: May 19, 2011, 06:02:11 pm »
hey I asked about variant 1  :D
it's k i thought it is variant 2

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #638 on: May 19, 2011, 06:03:20 pm »
need help with m/j 2009 variant 2 q 5b
i found something written here variant 2 (it's k this also helped me in practicing this question)

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #639 on: May 19, 2011, 06:06:19 pm »
i found something written here variant 2 (it's k this also helped me in practicing this question)

oops! my bad.. sorry  :-[
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #640 on: May 19, 2011, 06:07:10 pm »
Ok what you did using v=f*lambda is that you found the range of possibilities of lambda...
To find out about all the wavelenghts remember tht for destructive interference the phase difference or path difference should be equal to 1/2 lamda or 3/2 lambda or 5/2 lamda and soo onn. So you just find the lambda by 28x2 or 28x2/3 or 28x2/5 etc... and then count ho wmany wavelelgnths you have in the range.....

ohh! so thats how you do it! thanks  ;D
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #641 on: May 19, 2011, 06:09:13 pm »
oops! my bad.. sorry  :-[
it's all right

Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #642 on: May 19, 2011, 06:13:39 pm »
ohh! so thats how you do it! thanks  ;D
glad to hellp :)

Offline polltery

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #643 on: May 20, 2011, 10:33:19 am »
plz help me out wid this! cant understand the method used here ? ???

Offline Ghost Of Highbury

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #644 on: May 20, 2011, 11:04:18 am »
plz help me out wid this! cant understand the method used here ? ???

Draw tangent to the curve at 0.4s, calculate the gradient of the tangent.
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