Electromagnetic induction (1 Viewer)

[alexandrac]

How does electromagnetic induction work in cooktops and electromagnetic braking?

 

[Squar3root]

In cook tops, when an AC current is fed through the solenoid, the changing magnetic field is aimed at the bottom of the base pan and little eddy currents are induced which cook the food. Similarly in braking, the solenoid "emits" a changing magnetic field and due to Lenz's law and slows the train down

 

[MilkDrinker]

I suggest reading the pages about in the textbook in2physics.
I think it covers it quite well.

 

[hit patel]

I might just as well explain it milk, saving him the trouble:
So an AC current passes through a coil underneath the cook-top. The change in flux over time causes an emf to be induced in the cook-top by Faraday's Law. This change in flux due to the alternating of AC current at a certain frequency. This emf however doesn't have a fixed conducting path to travel through so the current induced is circular. These are eddy current and by Lenz's Law oppose the original change in flux, however the motion of these circular / elliptical currents through the plate causes resistance to come into effect. This releases energy as heat.
Electromagnetic Braking is caused when wheels have electromagnets at opposite ends. When the electromagnet is turned on and current passes through the electromagnet. This causes a change in flux passing through the ends of the wheels. This in-turn produces and emf at each ends of the wheel by Faraday's Law. However by Lenz's Law an induced current is formed which opposes the change in flux and thereby also opposes change in motion causing the wheel to slow down.
Hopefully that helps. In an exam I would draw diagrams to show an example for both because it feels like that this is not enough for 3-4 marks provided for either one.

 

[QZP]

There are some iffy parts in your response hit patel.

"This emf however doesn't have a fixed conducting path to travel through so the current induced is circular. These are eddy current and by Lenz's Law oppose the original change in flux, however the motion of these circular / elliptical currents through the plate causes resistance to come into effect"

It's not that they are circular due to a lack of "wire" and it's not that their circular nature cause heat production.

Don't like your response for electromagnetic braking either. Not sure if it was a rushed thing but yeah, just trying to help.