1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Plane immersed in the earth's vertically downward-pointing magnetic field

  1. Oct 24, 2011 #1
    1. The problem statement, all variables and given/known data


    This question and the next two refer to this situation:

    http://i.imgur.com/dgJMR.png

    dgJMR.png

    A passenger jet is flying over Alaska in level flight at a constant altitude h = 10 km and constant speed of v = 300 m/s, immersed in the earth's vertically downward-pointing magnetic field of B = 30 μT. The distance between the tips of the aircraft's metal wings is d = 50 m.

    Part A:
    Calculate the potential difference ε between the aircraft's wing tips due its motion through the earth's magnetic field.
    (a) ε = 0.0 volts
    (b) ε = 0.45 volts
    (c) ε = 0.90 volts

    Answer is B

    Part B
    Which wingtip has positive charge, as viewed by a passenger in the airplane who is facing in the direction that the airplane is traveling?
    (a) the right wingtip
    (b) the left wingtip
    (c) neither wingtip

    Answer is B



    2. Relevant equations

    emf = d flux / dt

    flux = int[B*dA]

    3. The attempt at a solution

    For part A, I tried formula above, I get answer C, because I thought I need to calculate difference for both wings? Part B I used F=BIL, however, I get the force is on right wing? What is the relationship between force ans its direction of the plane that traveling?

    Thx
     
  2. jcsd
  3. Oct 24, 2011 #2

    Delphi51

    User Avatar
    Homework Helper

    For part A, I used the generator formula V = L*v*B = 50*300*30x10^-6 = 0.45 Volts. Had I used only one wing length I would have gotten half that voltage.

    Part B is not a formula question. Use hand rules to figure out which way the electrons are pushed. Then you can tell which side is negative and which is positive.
     
  4. Oct 25, 2011 #3
    Everything makes sense now, thanks!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Plane immersed in the earth's vertically downward-pointing magnetic field
Loading...