Thank you so much for all your magnetic field videos dude. Idk if you read comments but I really appreciate it all. I am revising for A-level physics (summer 2022) and your magnetic field videos explain things much better than my teacher did. I understand things a lot better now
By far the best EMF definition I've seen. By far the best series of explanation. Way better than my teacher's explanation. I understand what they've been saying eay better now
When the plane moves through the field lines why does the flux through it actually change? Isn't the whole 'area' of the plane in the field the whole time? Sorry if this is a silly question in just a bit confused.
+WhiteKyurem456 No, that's a valid question. When any wire/plane cuts flux i.e. moves perpendicularly to the magnetic field, emf is induced. It's only with a coil that we talk about an emf being induced if the flux "filling" the coil changes - this is just a model to describe what's happening. In reality, it's still just wires cutting flux.
When you are using Change in B in the initial eqn (around 14:00) the change is negative, so it should surely be -0.2Ts^-1 not 0.2Ts^-1, However this would make sense to cancel out when inputing the negative sign due to lenz's law. Is that why you haven't included it or have I made a mistake?
Maybe, but I think since he is giving an example in the context of AC current, which would imply the sign changes many times a second, there would be a greater incentive to know the magnitude and not worry about the sign. So at t=0.05, the sign would be, say, positive; at t=0.1, the sign would be negative. So it wouldn't really matter which sign is associated, and we can forget about Lenz's law and keep the equation to ε = ΔΦ / Δt in order to calculate just the magnitude. I know I'm well over a year late but I hope someone has already clarified this for you.
For the plane example at the end, surely the induced EMF will be 0 as when it's moving through the field the rate of change of flux density is 0. Surely you are only interested in the area swept out when it is entering the field ? Many thanks
Surely! Surely! 😂 There is no 'loop' of wire here - we treat the plane as just a piece of wire, which I should have made clearer. Therefore the emf=BLv, just like a wire.
@@ScienceShorts surely (😂) this means that the wire doesn't require a change in magnetic flux for an EMF to be induced which goes against what Faraday said. Is it different for a wire and a loop then ? If so why?
It is experiencing a change in flux as it's cutting flux lines. The confusion is really with the loop - the whole 'how much flux fills it' is just a way of explaining what really is going on: as both sides of a loop move through the field, they experience the same emf, so cancel each other out. Hence why you only get an emf when only one side is in the field.
Hi, Great video! You mentioned on the example of the coil that only when flux is changing an emf is produced, when the coil is fully in the magnetic field no emf is produced. But in the last example the plane is always fully inside the magnetic field, so how is an emf produced? Thanks
Remember that a coil is effectively 2 lengths of wire (we don't care about the parallel bits) - when they're both cutting flux, the both have the same emf induced in them, so no current can flow in the coil.
Omg I was litterelly watching the video now and I had the same question and then you answered it just in time .i have been planning to watch the vid for 3 days cause I've got a test .thank you soooo much for the video .you explain things very well and have made me gain my hope in getting a good grade in physics(:(:(:(:(:
Don’t hold me to this but I think it’s because it’s the horizontal velocity (so horizontal distance per second) and so multiplying it by the vertical distance creates the value of the area
4:58 In the aqa a level physics formula booklet, there is no negative sign for the change in flux/change in time. If they ask us to derive it, shall we put the negative sign or not? Many thanks for the videos, there saving my physics a level.
Many thanks:) In the aqa a level physics oxford revision guide it talks about back EMF but when you look in the specification there is no mention of it what so ever. Should I still learn it?
also you derived an eqation, E=BLv, why does this not apply in the second part of the video where the coil moves through the magnetic field perpendicularly and there is no induced e.m.f.?
@Science Shorts I don't understand why for a loop, an emf is only produced when it is entering or exiting a field, but for a straight wire, an emf is produced when it moves anywhere in the field. Could you explain? :)
