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Stuck on a past paper question - HSN forum

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Stuck on a past paper question


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#1 kamran

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Posted 12 May 2007 - 08:57 PM

aight guys, just stuck on a past paper question. its the 2003 paper, Q28) B)ii

any help, would be appreciated.

#2 william

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Posted 13 May 2007 - 10:47 AM

its all to do with waves and interference,
if waves are in phase they will undergo constructive interference and produce a maximum ( e.g loud)
but if waves are out of phase then they will undergo destructive interference and cancel out to give a minima ( e.g no sound)

hope this helps like smile.gif
"millis times ten to the power of minus 3 yeah?"

#3 kamran

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Posted 13 May 2007 - 11:12 AM

thz mate, but how am i meant to know that destuctive interference is occurung inside the headphones??

#4 william

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Posted 13 May 2007 - 01:27 PM

well i guessed the pilot didnt want to get his ears really hurt from the sound!
"millis times ten to the power of minus 3 yeah?"

#5 verticalforce

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Posted 13 May 2007 - 09:16 PM

crest meets crest, trough meets trough = constructive

crest meets trough, trough meets crest = destructive

I've checked the marking instruction and this would have given you the same marks as explaining how the waves are in phase/out of phase.

A diagram instead of explanation is acceptable too.





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