Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    1
    ReputationRep:
    Two coherent sources emit waves of wavelengths lamda in phase. At a point where the two wavaes smeet they have aphase difference of 90 degrees . Which of he following could be the path difference?
    A 2lamda
    B lamda
    c lamda /2
    D lamda/4
    Offline

    13
    ReputationRep:
    (Original post by Rosie1999)
    Two coherent sources emit waves of wavelengths lamda in phase. At a point where the two wavaes smeet they have aphase difference of 90 degrees . Which of he following could be the path difference?
    A 2lamda
    B lamda
    c lamda /2
    D lamda/4
    Name:  Photo on 03-06-2016 at 08.53.jpg
Views: 40
Size:  123.6 KBPath difference is the difference in distance traveled by the two waves from their sources to a given point on the pattern. In order to get a phase difference of 90 degrees, you need to start one wave from lambda/4 behind the other.
    Another way to think of it for coherent waves is to say that lambda = 360 degrees, so lambda/2 = 180 degrees and lambda/4 = 90 degrees.
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by Laurasaur)
    Name:  Photo on 03-06-2016 at 08.53.jpg
Views: 40
Size:  123.6 KBPath difference is the difference in distance traveled by the two waves from their sources to a given point on the pattern. In order to get a phase difference of 90 degrees, you need to start one wave from lambda/4 behind the other.
    Another way to think of it for coherent waves is to say that lambda = 360 degrees, so lambda/2 = 180 degrees and lambda/4 = 90 degrees.
    how do you know lambda is equal to 360?
    Thanks for your expalnation tho and graoh so much better. and do you have sheets for revision ? or notes for that lesson ?
    Offline

    3
    ReputationRep:
    (Original post by Rosie1999)
    how do you know lambda is equal to 360?
    Thanks for your expalnation tho and graoh so much better. and do you have sheets for revision ? or notes for that lesson ?
    lamda/ 1 complete wavelength is when a particle on a wave completes a whole oscillation. In other words the particle moves through 360deg
    Offline

    13
    ReputationRep:
    (Original post by Rosie1999)
    how do you know lambda is equal to 360?
    Thanks for your expalnation tho and graoh so much better. and do you have sheets for revision ? or notes for that lesson ?
    Did you learn about sine waves in gcse maths? Basically, 1 complete oscillation is 360 degrees (also 2 pi radians), like completing a circle. It's just something you'll have to rememberName:  c9P9FPl.gif
Views: 36
Size:  129.4 KB
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Has a teacher ever helped you cheat?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Write a reply...
    Reply
    Hide
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.