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Homework Help: Electromagnetic Waves

  1. Apr 13, 2008 #1
    Suppose some astronauts have landed on Jupiter.
    (a) When Jupiter and Earth are on the same side of the Sun and as close as they can be to one another, how long does it take for radio transmissions to travel one way between the two planets?

    Suppose the astronauts ask a question of mission control personnel on Earth. What is the shortest possible time they have to wait for a response? The average distance from Jupiter to the Sun is 7.78 E11 m.

    - i figured the the answer to a) would be distance divided by the speed of light but that isnt getting me anywhere
    -i dont even know where to begin on the second one
  2. jcsd
  3. Apr 13, 2008 #2


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    Homework Helper
    Gold Member

    You are correct that the answer to part a) is:



    For part a) You need to know how far apart Jupiter and Earth are for this case. How far is the Earth from the sun? How far is Jupiter from the sun? Can you now find how far apart the two planets are when they are on the same side of the sun? It may help to draw a picture.

    For part b) Remember that the astronauts have to wait for their radio message to get to earth, and then they have to wait for the response to travel back to them. Using what you know from part a), how long does this whole process take?
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