Faraday's Law: induced EMF when the magnetic flux changes, example of magnetic field through a loop.
New videos every week! Subscribe to Zak's Lab / @zakslab
Questions or requests? Post your comments below, and I will respond within 24 hours.
In this discussion of Faraday's Law, induced emf is determined by first motivating the definition of magnetic flux in terms of area, the intensity of the magnetic field and the angle between the normal vector and magnetic field, then stating the physical principle that nature abhors a change in flux. This is another way of stating Lenz's law: when the magnetic flux through a loop changes, a current (or at least an emf) is induced that opposes the magnetic flux change.
Next, we motivate and quantify the magnitude of the induced emf. This gives us Faraday's Law, which quantifies the induced emf in terms of the number of loops and the time rate of change of the flux.
In our example, we are given a coil of known dimensions, and we turn on a magnetic field in a known amount of time. We calculate the induced emf and the induced current, given the resistance of the coil.
