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Phase and Phase difference.....Can somebody enlighten me?

  1. Jun 2, 2016 #1
    I'm currently studying wave mechanics(high school level), and more thing that makes scribble all over is the concept of phase and Phase difference. After these long tries, I could mathematically think of what they are, but cannot geometrically or logically express it. Can someone help me out.....
    Last edited by a moderator: Jun 2, 2016
  2. jcsd
  3. Jun 2, 2016 #2


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    Draw a regular sine waves on a graph and then draw another one shifted over to the right a bit from the regular one. The shift is the amount of phase difference.
  4. Jun 2, 2016 #3


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    Phase is the argument of the trig-function describing the wave...
    the "angle-reading on a protractor", or think of the second-hand on an analog clock.
    Phase-difference is the difference in phase (phase now - phase before)...
    the difference in angle-readings, or the angle between the angular positions of the second-hands.
    (Technically, one may have to include full revolutions in certain cases..)
  5. Jun 2, 2016 #4
    Or can I say like this...phase is the condition/position of a particle at a particular point and at a particular instant of time in a travelling wave, and difference between trigonometric arguments of a particular particle at different instants of time is phase difference. Is that right? Anything to add more?
  6. Jun 3, 2016 #5
    Particles with the same phase in a wave are in similar positions. But the phase is not the position.
  7. Jun 3, 2016 #6


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    I would say that 'phase' is referrenced to a particular, chosen time or position of the wave or signal in question. 'Phase Difference' is referred to another wave or signal.
    People may not be too fussy about how the terms are used. Context should make it clear which is the intended meaning.
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