[kergonath]

> I guess you could have a hot spot on the pan if the coils are ill-designed or you’re putting a large pan on a small burner?

Yes, but then it’s hardly a problem with the technology if you put a large pan on a small burner.

As for the rest, in all cookers I have seen, the coils cover the whole surface, except for a small spot in the centre. Besides, induced current does not happen only where the cookware is closest to the coil. The magnetic field is more spread out than that and the heating surface is larger than just the surface of “contact” (there is no real contact, but anyway).

I assume there could be an exceptionally badly designed induction cooktop with hot spots (it’d have to have a very weird geometry, though), but that would take some effort.

[ants_a]

With most cookware it's pretty obvious where the coils are when trying to simmer. With thinner stuff like carbon steel the hot spots can be pretty nasty: https://www.youtube.com/watch?v=pifD__DIxGU