# Does an emf in an aeroplane's wings result in a current? [closed]

In part (b) of this question, they have stated that the current that flows through the aeroplane is 0.00 A. When you use the value for emf from part (a) and the resistance, you can calculate that I = V/R = 0.490/1.78 = 0.275 A. I don't understand how they concluded that there must be no current in this situation; they must have also concluded it without doing any calculations for the question was only one mark.

Research:
Passing through the earth's magnetic field This link says that a current is indeed produced, which doesn't answer my question.
What is the effect of Earth’s magnetic field on airplanes? Here, they have stated that the resistance is great for a current. However, as shown above, the current in this question is still big enough for it to have an answer to 3 signficant figures, so I believe that this question is not assuming that the resistance is too large.
Emf induced on the wings of an airplane This article seems the most relevant. It says that the magnetic flux is not changing so there are no eddy currents created. So does that mean that the emf caused by the movement of a conductor through a magnetic field (ε=lvB) never produces current? It has to be emf caused by Faraday's law which causes a current?

Also, can you explain it through the fact that if the magnetic field is producing a force pushing the electrons to one side of the plane, the electrons can't travel the other way to go round the circuit and produce a current?

• The wire that you use to connect the wings is also in the magnetic field. What's the EMF on the wire? Commented Sep 21, 2023 at 5:44
• The same as the plane? Commented Sep 21, 2023 at 6:03
• So the net emf is? Commented Sep 21, 2023 at 7:22
• 0.490V still but it didn't make sense to me why there could be an emf but no current Commented Sep 21, 2023 at 8:30
• That is not the net emf in the complete circuit. You have a loop travelling through a region of constant magnetic field. Commented Sep 21, 2023 at 11:17

The force on an electric charge $$q$$ is given by the Lorentz force equation
$$\vec F=q \vec E + q \vec v \times \vec B$$
where $$\vec E$$ is an electric field, $$\vec B$$ the magnetic field and $$\vec v$$ the velocity of motion of the charge. The movement of the free electrons in the metal wing through the magnetic field leads to a force that displaces the electrons towards one end of the wing, which becomes negatively charged, and leaves a net positive charge at the other end. The movement of electrons represents a current flow in the wing but this occurs only for a very short time (when the plane first starts moving or when it first flies into the magnetic field). Very quickly the charge difference builds creating an electric field $$\vec E=-\vec v \times \vec B$$ that eventually balances the magnetic force, whereby $$\vec F=0$$. This opposing electric field results in a zero net current flow in the wing but creates a potential difference. It is this potential difference, also known as an electromotive force $$\mathcal E=\int \vec E \cdot d \vec l$$, that is calculated in the problem.