In this Crash Course video, from 5:57 to 6:15, I think the directions are mixed up, but I could be wrong. She says that when moving the magnet into the loop, the generated magnetic field is pointing upward. She says that therefore, the current will be moving clockwise along the loop. And she says when the generated magnetic field is pointing downward, the current will be moving counter-clockwise. But if you point your thumb in the direction of the magnetic field (up in the first example), using the right hand rule, shouldn't current be flowing counter-clockwise? And vice versa? I'm not sure if I'm getting this wrong because I'm not understanding Lenz's law or if the video is incorrect on the directions.
[Physics] Magnetic field generated pointing upwards, what direction is induced current
electricityelectromagnetisminductanceinduction
Best Answer
I think it should be "when moving the magnet into the loop, the generated magnetic field is pointing downward". This is how the generated current tries to resist the increase in magnetic field when the magnet moves upward into the loop.
Or we can think in this way. There are magnetic field lines going from the center radially outward from N to S. And the magnet being moving upward is just equivalent to the coil moving downward. By $\vec{F}=q\vec{v}\times \vec{B}$, the positive charges ($q$) in the wire (let's use positive charge as it is easier than considering electron, which will give the same end result) moving downward will experience a force to move in the direction so that the current is moving clockwise and this will generate a magnetic field pioint downward too.