a lvl phy qn

• ohnoez!

  2 Sep 10, 22:38

  can someone explain the solution to part ii 2 and iii? how come 1.25wavelength path diff is total destructive interference? how come at 440m there is constructive interference when path diff is 0.5wavelength?

  

  soln here

  

• ohnoez!

  4 Sep 10, 16:06

  helppppppppp

• wee_ws

  5 Sep 10, 12:53

  Hi,

    This may help:

    http://answers.yahoo.com/question/index?qid=20090604201516AAHJ097

    Thanks.

  Cheers,
  Wen Shih

• ohnoez!

  5 Sep 10, 18:23

  that didnt helped =( thx anyway

• eagle

  6 Sep 10, 00:14

  haha my student asked the same question... She's not online, if not I will get her to explain. :x

  
  Basically, it is not 0.5 wavelength path difference. You have to take into account that when the distance from one end reduces by 0.5 wavelength, the distance from the other end increases by 0.5 wavelength.

  Hence in total, the path difference would have increased by 1 full wavelength, and not 0.5 wavelength.

   

  ")

• ohnoez!

  6 Sep 10, 20:11

  oic ty