Author Topic: waves help  (Read 1387 times)

Offline AN10

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waves help
« on: March 21, 2010, 12:26:41 pm »
plz solve question no 5 of first variant paper attached below
“Faith is taking the first step even when you don't see the whole staircase.”

Offline vanibharutham

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Re: waves help
« Reply #1 on: March 21, 2010, 01:10:04 pm »
For a wave to a have a minima, there must be destructive interference i.e. a phase difference of Pi radians...

However to detect a minima of ZERO, you must have a) A phase difference of Pi Radians b) Same Amplitude




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Offline AN10

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Re: waves help
« Reply #2 on: March 21, 2010, 01:32:10 pm »
k i get it.... can u plz solve da second part too
“Faith is taking the first step even when you don't see the whole staircase.”

Offline AN10

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Re: waves help
« Reply #3 on: March 22, 2010, 10:49:38 am »
anyone ??? ???
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Offline astarmathsandphysics

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Re: waves help
« Reply #4 on: March 22, 2010, 11:37:20 am »
I will do it when I get home in 1 hour

Offline astarmathsandphysics

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Re: waves help
« Reply #5 on: March 22, 2010, 12:32:45 pm »
Distance frim S_2 to M is sqrt(1^2 +0,8^)=1.28m
so path difference =0.28m
when f=1kHz wavelength=v/f=330/1000=0.33
When f=4kHz wavelength=330/4000=0.0825
minumum whenw/2=28 or 3w/2 =28 or 5w/2=28 or 7w/2 =28
w=56 or w=18.7 or w=11.2 or w=8
only two of these are between 8.25 and 33
so only two minima

Offline AN10

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Re: waves help
« Reply #6 on: March 22, 2010, 02:15:23 pm »
ok....thanx a lot!!
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Offline halosh92

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Re: waves help
« Reply #7 on: March 27, 2010, 05:34:41 pm »
Distance frim S_2 to M is sqrt(1^2 +0,8^)=1.28m
so path difference =0.28m
when f=1kHz wavelength=v/f=330/1000=0.33
When f=4kHz wavelength=330/4000=0.0825
minumum whenw/2=28 or 3w/2 =28 or 5w/2=28 or 7w/2 =28
w=56 or w=18.7 or w=11.2 or w=8
only two of these are between 8.25 and 33
so only two minima

i dont get this part only:
minumum whenw/2=28 or 3w/2 =28 or 5w/2=28 or 7w/2 =28
everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline astarmathsandphysics

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Re: waves help
« Reply #8 on: March 27, 2010, 06:55:01 pm »
w is the wavelenfth and mimima where paths difference  is w/2 or 3w/2 etc

Offline astarmathsandphysics

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Re: waves help
« Reply #9 on: March 27, 2010, 06:55:35 pm »
cos that means destructive interference