Motional emf Definition and 11 Discussions

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  1. Ahmed1029

    I Is electromotive force always equal to potential difference?

    In the case motional emf, there is a static magnetic field and a rectulgular loop that goes into the field region, then current is produced. There is no electric field, but there is an emf. However, Griffiths states that emf is equal to the potential difference between the source endpoints. But...
  2. VVS2000

    I Motional EMF induced between the ends of the rotating rod

  3. SpectraPhy09

    Motional EMF problem

    I request please go through my solution Total Resistance = R + 2λx V(ind) = vBd I(ind)= vBd/(R + 2λx ) v = i(R + 2λx )/Bd If force on the wire due to induced current is iBl then Fnet = iBd - F ...(i) or Fnet = F - iBd ...(ii) Fnet = v(dv/dx) v(dv/dx) = iBd - F By solving...
  4. B

    Motional EMF for loops of wire vs conducting plates

    I'm in an intro E&M class, and I'm trying to distinguish between Motional EMF for loops of wire and conducting plates. This question might be kind of silly, but are Eddy currents pretty much the same thing as induced currents in a loop of wire? More specifically, what I am trying to ask is if...
  5. christang_1023

    Solve the differential equation of motional emf

    . Above is the figure of the problem. I am trying to solve x(t) and differentiate it to obtain v(t); however, I have difficulty solving the differential equation shown below. $$ v(t)=\int a(t)dt=\int \frac{B(\varepsilon-Blv)d}{Rm}dt \Rightarrow \frac{dx}{dt}=\frac{B\varepsilon...
  6. A

    EMF about a loop moving toward a wire with current

    Homework Statement A picture of a related problem is attached below. My problem is the same, except that v is toward the wire, not away from it. I, r, v, b and a are given. "Find the emf about the loop without assuming that B changes at any point" My problem is that this question isn't...
  7. kostoglotov

    Lenz's Law applied to a non-circuit conductor?

    I was reading through my College Physics text, and it talked about how NASA once swung a 20km long conductor through the Earth's magnetic field and setup a 3500V potential difference along the wire. I understand that there's no conventional current in that wire, it's not a circuit. But for a...
  8. Gerry Rzeppa

    Motional EMF and Electrons

    Here is a typical description of motional EMF: "The figure below shows a conducting rod of length L being moved with a velocity v in a uniform magnetic field B: The magnetic force acting on a free electron in the rod will be directed upwards. As a result, electrons will start to accumulate...
  9. Kerrigoth

    Are induced currents created by motion or change in flux?

    The book I am working through is beginning to dive into induced currents and Lenz's Law. When a conductor is moving perpendicular to a magnetic field, the charge carriers inside will experience a magnetic force; This causes the charges to move. Eventually, the electric field from the charge...
  10. fricke

    Motional EMF

    I understand that EMF is generated by moving a closed loop of wire through a constant magnetic field. I am confused about one thing, who is actually doing work here? (of course it is not magnetic field).
  11. patrickbotros

    Direction of Current in a Sliding Bar

    I'm studying for the Physics SAT Subject Test using The Princeton Review (2011-2012). There's this motional EMF problem about a rod sliding to the right along a u-shaped wire in a uniform magnetic field that's going into the page and the current moving counter clockwise. Problem is: I can't...