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Electromagnetic Induction? HELP

  1. Dec 7, 2009 #1
    Electromagnetic Induction!? HELP !!

    1. The problem statement, all variables and given/known data
    1.
    A single horizontal loop of wire is moving in a horizontal plane at a constant speed across a uniform vertical magnetic field that "fills" and surrounds the loop. The emf induced across its terminals will be ....??
    the answer was "none of these" =not constant, negative, positive...
    What can be the answer then??!

    2.
    A solenoid is physically altered by doubling the number of turns it has while halving the current through it, leaving everything else unchanged.
    Answer: its self-inductance is four times greater.

    3.
    A small light bulb is in series with an air-core coil and a dc power supply such that the lamp glows brightly. An iron core is then inserted into the coil, and an hour later the lamp...!??
    The answer was none of these...

    what can be the answer then??!



    Please HELP !! ASAP !! Thank you for your kind help!!!
     
  2. jcsd
  3. Dec 7, 2009 #2

    diazona

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    Re: Electromagnetic Induction!? HELP !!

    None of what?

    What have you tried? If you're given some answer choices, which one, if any, seems correct to you, and why?
     
  4. Dec 7, 2009 #3
    Re: Electromagnetic Induction!? HELP !!

    For 1 and 3,, the answer was none of these..for 1 not positive, constant..etc.

    SO, I was wondering what would happen(answer)?What would be the answer?

    I now understand number 2..
     
  5. Dec 7, 2009 #4

    Redbelly98

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    Re: Electromagnetic Induction!? HELP !!

    For (1), use the equation for induced EMF. (You should have included this as a Relevant Equation when you submitted your questions.)
     
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