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Light (radiowaves) question help

  1. Nov 18, 2012 #1
    1. The problem statement, all variables and given/known data
    Radio waves (speed=c) from a two point source produce an interference pattern in space. Your house is located at a point where the path difference from the two radio sources is 1500 m. If the radio frequency is 500 kHz, show whether your house is on a node or an antinode. Answer =node, lousy reception

    2. Relevant equations

    3.The attempt at a solution
    I figured out the lamda by dividing C by f first and it came out to be 600m , but 1500m is not a COMPLETE divisible of 600m and results in N being = 2.5 which means that it should be an antinode however the answer says that its a node, am I doing something wrong? Please help. Thank you :)
  2. jcsd
  3. Nov 18, 2012 #2


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    What is node, and what is antinode? What should be the path difference to get a node/antinode?

  4. Nov 18, 2012 #3
    A node is when there is a constructive interference and an antinode is when there is a destructive interference. Path difference should be an integer. Like 1λ or 2λ for nodes , and for antinodes should be 1.5λ or 2.5λ. Am I right?
  5. Nov 19, 2012 #4
    Oh sorry, I was wrong all the time. Node is destructive interference and anti node is constructive :P .. haha :P sorry
  6. Nov 19, 2012 #5


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    That is right. :smile: 'In general, a node is a localised swelling (a "knot") or a point of intersection (a vertex)' /Wikipesia.

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